chore(dev): replace gitpod with devcontainer

.devcontainer/Dockerfile

@@ -0,0 +1,8 @@
+FROM ubuntu:noble
+ARG PYTHON_PACKAGES="python3.13 python3.12 python3.11 python3.10 python3.9 python3.9-distutils python3 python3-pip python3-venv pipx"
+RUN apt-get update \
+    && apt-get install --no-install-recommends -yq software-properties-common git \
+    && add-apt-repository ppa:deadsnakes/ppa && apt-get update \
+    && apt-get install -yq --no-install-recommends ${PYTHON_PACKAGES} \
+    && pipx ensurepath \
+    && pipx install tox

.devcontainer/devcontainer.json

@@ -0,0 +1,30 @@
+// For format details, see https://aka.ms/devcontainer.json. For config options, see the
+// README at: https://github.com/devcontainers/templates/tree/main/src/python
+{
+    "name": "Python 3",
+    "build": {
+        "dockerfile": "Dockerfile"
+    },
+    // "features": {
+    // 	// Rust is necessary for the `nh3` package if wheels are unavailable.
+    //  // The current Python versions tested have wheels, so this is commented out.
+    //    "ghcr.io/devcontainers/features/rust:1": {}
+    // },
+    // Use 'postCreateCommand' to run commands after the container is created.
+    "postCreateCommand": "bash .devcontainer/post-create.sh",
+    // Configure tool-specific properties.
+    "customizations": {
+        "vscode": {
+            "extensions": [
+                "EditorConfig.EditorConfig",
+                "ms-python.python",
+                "ms-python.mypy-type-checker",
+                "tamasfe.even-better-toml"
+            ]
+        },
+        "settings": {
+            "python.defaultInterpreterPath": ".venv/bin/python",
+            "python.terminal.activateEnvInCurrentTerminal": true
+        }
+    }
+}

.devcontainer/post-create.sh

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+set -e
+
+# `tox` testing manages its own environments
+# Create virtualenv for local development, editor completion, etc.
+python3 -m venv .venv
+source .venv/bin/activate
+pip install --upgrade pip
+pip install -e .[md]

.github/CONTRIBUTING.md

@@ -0,0 +1,52 @@
+# Contributing
+
+The following is a set of guidelines for contributing to this project.
+These are just guidelines, not rules.
+Use your best judgment, and feel free to propose changes to this document in a pull request.
+
+## Development Setup
+
+### The Easy Way
+
+Use the supplied [Development Container](https://containers.dev/) configuration
+to get a development environment up and running quickly.
+The configurations can be found in the `.devcontainer` directory.
+
+[GitHub Codespaces](https://github.com/features/codespaces) can provide
+a development environment in the cloud.
+GitHub Codespaces also provides a prebuilt image for this repository
+from the most recent commit on the `main` branch
+to speed up the setup process, including many of the Python runtimes
+and tools needed to run the tests.
+
+Other tools like Visual Studio Code may use the devcontainer configuration
+to provide a consistent development environment locally,
+if you have a compatible version of a container runtime.
+
+### The Less-Easy Way
+
+1. Fork the repository and clone it to your local machine.
+1. Install any Python runtimes you wish to test against.
+1. Install the `tox` test runner
+
+Note: You may need other development tools depending on the environment you are working in.
+
+## Running Tests
+
+Once started up, in a shell, run `tox -l` to see the available test environments.
+To run the tests, use `tox -e <environment>`
+where `<environment>` is one of the environments listed by `tox -l`.
+
+Alternatively, you can run `tox` without any arguments to run all the tests.
+
+### Parallel Testing
+
+To run all Python tests in parallel on all available CPUs:
+
+    tox -p auto
+
+Read more about [parallel mode](https://tox.wiki/en/latest/user_guide.html#parallel-mode).
+
+## Testing Guidelines
+
+TODO: Explain test fixtures and how to create/update them.

.gitignore

@@ -5,6 +5,7 @@ dist/
 htmlcov/
 
 .tox/
+.venv/
 .cache/
 .coverage
 *.egg-info/

README.rst

@@ -29,8 +29,15 @@ Everyone interacting in the readme_renderer project's codebases, issue trackers,
 chat rooms, and mailing lists is expected to follow the `PSF Code of Conduct`_.
 
 
+Contributing
+------------
+Contributions are welcome, and they are greatly appreciated!
+Every little bit helps. See `CONTRIBUTING.md`_ file for more information.
+
+
 .. |twine check| replace:: ``twine check``
 .. _twine check: https://packaging.python.org/guides/making-a-pypi-friendly-readme#validating-restructuredtext-markup
 .. _PSF Code of Conduct: https://github.com/pypa/.github/blob/main/CODE_OF_CONDUCT.md
+.. _CONTRIBUTING.md: https://github.com/pypa/readme_renderer/blob/main/.github/CONTRIBUTING.md
 
 Copyright © 2014, [The Python Packaging Authority].

pyproject.toml

@@ -51,6 +51,10 @@ Home-page = "https://github.com/pypa/readme_renderer"
 requires = ["setuptools>=40.8.0"]
 build-backend = "setuptools.build_meta"
 
+[tool.check-manifest]
+ignore = [
+  ".devcontainer/*",
+]
 
 [tool.coverage.run]
 branch = true