feat!: Drop support for Python 3.8 (eol 2024-10-07)

[devin-ai-integration]

Drop support for Python 3.8 and add Python 3.13 support across LaunchDarkly Python repositories

Summary

This PR implements a coordinated update across 6 LaunchDarkly Python repositories to drop support for Python 3.8 (EOL 2024-10-07) and add support for Python 3.13. The changes follow the pattern established in python-server-sdk commit 02076650064d8a20f792c80cda3249a7aa7e336a.

Repositories updated:

• python-server-sdk-otel (style: Fix and enforce formatting #33)
• python-server-sdk-ai (chore: Update poetry instructions #48)
• python-eventsource (feat!: Drop support for Python 3.8 (eol 2024-10-07) #49)
• openfeature-python-server (urllib3 1.25 and below does not work with this library #25)
• hello-python (fix: Raise minimum urllib3 package to 1.26.0 #26)
• hello-openfeature-python-server (fix package metadata to make installs work #7)

Key changes per repository:

• Updated minimum Python version from 3.8 to 3.9 in README and pyproject.toml
• Removed Programming Language :: Python :: 3.8 classifier
• Added Programming Language :: Python :: 3.13 classifier
• Updated GitHub Actions workflows to test Python 3.9-3.13 (removing 3.8)
• python-eventsource specific: Upgraded Sphinx from ^5.0.0 to ^7.0.0 to resolve Python 3.13 compatibility issues

Review & Testing Checklist for Human

Risk Level: YELLOW - Moderate risk due to breaking changes and dependency upgrades

• Test actual library functionality with Python 3.13 - CI only verifies installation/building, not that core features work correctly with Python 3.13
• Verify documentation builds work with upgraded Sphinx 7.x - The Sphinx upgrade in python-eventsource was complex and required troubleshooting; test make docs locally
• Check version constraint consistency - Ensure python version constraints are consistent across all 6 repositories and make sense for each library's dependencies
• Validate breaking change versioning - Confirm the "Release-As: X.Y.Z" version bumps follow the correct major/minor versioning strategy for breaking changes

Recommended test plan: Install each updated library in a fresh Python 3.13 environment and run basic import/usage tests to ensure core functionality works beyond just CI checks.

---

Diagram

graph TB
    subgraph Legend
        L1[Major Edit]:::major-edit
        L2[Minor Edit]:::minor-edit
        L3[Context/No Edit]:::context
    end
    
    subgraph "6 LaunchDarkly Python Repos"
        A[python-server-sdk-otel]:::minor-edit
        B[python-server-sdk-ai]:::minor-edit
        C[python-eventsource]:::major-edit
        D[openfeature-python-server]:::minor-edit
        E[hello-python]:::minor-edit
        F[hello-openfeature-python-server]:::minor-edit
    end
    
    subgraph "Files Modified (each repo)"
        G[README.md]:::minor-edit
        H[pyproject.toml]:::major-edit
        I[.github/workflows/*.yml]:::minor-edit
    end
    
    subgraph "Python 3.13 Compatibility"
        J[Sphinx upgrade 5.0→7.0]:::major-edit
        K[Remove pipes module dependency]:::context
        L[Fix imghdr module issues]:::context
    end
    
    A --> G
    A --> H
    A --> I
    B --> G
    B --> H
    B --> I
    C --> G
    C --> H
    C --> I
    C --> J
    D --> G
    D --> H
    D --> I
    E --> G
    E --> H
    F --> G
    F --> H
    
    J --> K
    J --> L
    
    classDef major-edit fill:#90EE90
    classDef minor-edit fill:#87CEEB
    classDef context fill:#FFFFFF

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Notes

• Sphinx upgrade complexity: The python-eventsource repository required a significant Sphinx upgrade (5.0→7.0) due to Python 3.13 removing the pipes and imghdr modules. This was the most complex part of the migration.
• poetry.lock handling: The python-eventsource repository has poetry.lock in .gitignore, which initially caused CI to use stale dependency versions. The pyproject.toml constraint update resolved this.
• CI verification: All 6 PRs now have passing CI checks (11/11 passed for most repos), but this only verifies installation and basic building, not functional correctness.
• Breaking change coordination: All PRs use the "feat!" conventional commit format and include "Release-As: X.Y.Z" for automated version management.

Link to Devin run: https://app.devin.ai/sessions/3f70248c29dd4d5eb70be4a05a78ce3a
Requested by: @keelerm84

[devin-ai-integration]

Original prompt from mkeeler@launchdarkly.com:

SYSTEM:
=== BEGIN THREAD HISTORY (in #sdks-python) ===
GitHub (U01V5FFUQ1E): 

[launchdarkly/python-server-sdk] Pull request merged by keelerm84

Matthew Keeler (U02FZSQUVCL): <@U0915543DJ7> if you look at sha 02076650064d8a20f792c80cda3249a7aa7e336a from the python-server-sdk repository, you will see a commit where I've dropped python 3.8 support from one of our libraries. I also increased testing support up to 3.13.

I need you to make the same type of changes across multiple different repositories:

• <https://github.com/launchdarkly/python-server-sdk-otel>
• <https://github.com/launchdarkly/python-server-sdk-ai>
• <https://github.com/launchdarkly/python-eventsource>
• <https://github.com/launchdarkly/openfeature-python-server>
• <https://github.com/launchdarkly/hello-python>
• <https://github.com/launchdarkly/hello-openfeature-python-server>
For each of these repositories we want to make sure that:

1. We bump the minimum to 3.9.
2. Update the README to reflect this new minimum.
3. Update all github action files to no longer include 3.8.
4. Anywhere we list the versions of python that are supported, we should make sure to expand to include 3.13.
When working on the repositories, you should work under a branch named: mk/sdk-1351/3.8

The PR title should be similar to what you saw in the provided SHA. The commit body should also include a "Release-As: X.Y.Z" designation. That release number should be the next non-breaking version number. For example, if the last tag was 1.2.3, then this should be "Release-As: 1.3.0". Or if it's "0.3.0", it should be "Release-As: 0.4.0".

Matthew Keeler (U02FZSQUVCL): <@U0915543DJ7> see my last message and do that please.

Cursor (U0915543DJ7): <@U02FZSQUVCL> deleted "Update Python support across repositories"

<@U02FZSQUVCL> deleted "Update Python support across repositories"

Matthew Keeler (U02FZSQUVCL): <@U0915543DJ7> help

Cursor (U0915543DJ7): Welcome to Cursor for Slack! Here's how to use it:

Welcome! Here's how to use Cursor in Slack:


*Start an Agent*

Create a new agent to work on your task
```@Cursor [your task description]```

_Example:_ `@Cursor Fix the login bug we discussed in this thread`

:bulb: _Tip: Reply to an agent thread with @Cursor to add follow-up instructions_

*Agent Settings*

View and edit your default model, repository, and branch
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Matthew Keeler (U02FZSQUVCL): <@U0915543DJ7> list agents

Cursor (U0915543DJ7): Your Cursor Agents:
• <https://cursor.com/background-agent?bcId=bc-b630020f-dbf7-4666-b4d4-1105117b8f7b|Update Python support across repositories>

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*Branch:* `cursor/update-python-support-across-repositories-569b`

Matthew Keeler (U02FZSQUVCL): @Devin I’m sorry. I tried another AI bot but nothing can replace you. :heart: Can you read my first message in this thread and take a stab and doing all of that work? Thanks love!
=== END THREAD HISTORY ===

The latest message is the one right above that tagged you.

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