docs: add end-of-life date estimate to release documentation [DPCYMGMT-2234]

[emmettbutler]

This change adds an estimated end-of-life date to the release notes for all future minor releases by adjusting the release instructions. The date is heavily caveated and is estimated as "the same point in the major-version lifecycle as we are right now, but two major versions in the future".

Checklist

• PR author has checked that all the criteria below are met
• The PR description includes an overview of the change
• The PR description articulates the motivation for the change
• The change includes tests OR the PR description describes a testing strategy
• The PR description notes risks associated with the change, if any
• Newly-added code is easy to change
• The change follows the library release note guidelines
• The change includes or references documentation updates if necessary
• Backport labels are set (if applicable)

Reviewer Checklist

• Reviewer has checked that all the criteria below are met
• Title is accurate
• All changes are related to the pull request's stated goal
• Avoids breaking API changes
• Testing strategy adequately addresses listed risks
• Newly-added code is easy to change
• Release note makes sense to a user of the library
• If necessary, author has acknowledged and discussed the performance implications of this PR as reported in the benchmarks PR comment
• Backport labels are set in a manner that is consistent with the release branch maintenance policy

[github-actions]

CODEOWNERS have been resolved as:

docs/contributing-release.rst                                           @DataDog/python-guild

[github-actions]

Bootstrap import analysis

Comparison of import times between this PR and base.

Summary

The average import time from this PR is: 275 ± 2 ms.

The average import time from base is: 277 ± 2 ms.

The import time difference between this PR and base is: -1.93 ± 0.08 ms.

Import time breakdown

The following import paths have shrunk:

ddtrace.auto 1.992 ms (0.72%)

ddtrace.bootstrap.sitecustomize 1.291 ms (0.47%)

ddtrace.bootstrap.preload 1.291 ms (0.47%)

ddtrace.internal.remoteconfig.client 0.650 ms (0.24%)

ddtrace 0.701 ms (0.25%)

ddtrace.internal._unpatched 0.058 ms (0.02%)

json 0.032 ms (0.01%)

json.decoder 0.032 ms (0.01%)

re 0.032 ms (0.01%)

enum 0.032 ms (0.01%)

types 0.032 ms (0.01%)

subprocess 0.026 ms (0.01%)

contextlib 0.026 ms (0.01%)

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-07-09 19:20:57

Comparing candidate commit e08fb3e in PR branch emmett.butler/eol-estimate with baseline commit 9e5a5a0 in branch main.

Found 1 performance improvements and 1 performance regressions! Performance is the same for 545 metrics, 3 unstable metrics.

scenario:iastaspectsospath-ospathsplit_aspect

• 🟥 execution_time [+938.891ns; +1022.979ns] or [+19.021%; +20.725%]

scenario:span-add-metrics

• 🟩 max_rss_usage [-361.410MB; -293.816MB] or [-38.340%; -31.169%]

[brettlangdon]

I get the value, but I worry about the perception of marking an EOL date on minor versions.