[v1.12.1] Bug fixes regarding intersection env & enhancements regarding community contributions

[Trenza1ore]

HighwayEnv v1.12.1

This is a minor bug fix + maintenance release, mainly affecting the intersection environment and its variants.

Bug fix

• Prevent in-loop list mutation & removing controlled vehicles in rare cases by @Trenza1ore & @AntaresFeng (fix(intersection): prevent in-loop list mutation & removing controlled vehicles in rare cases #721)
• Validate nested config dicts in default_config override for all envs & fix default config for variants of intersection env by @Trenza1ore & @AntaresFeng (fix(envs): add nested config validation in default_config override #724)
• Prevent uint8 overflow of OccupancyGrid observation shape by @teddytennant & @Trenza1ore (fix: prevent silent uint8 overflow of OccupancyGrid observation shape #709)

Documentation

• Fixed documentation website's edit button by @Trenza1ore (docs: use correct source branch for docs edit button #708)
• Use the new celshast package for documentation theme by @Trenza1ore (chore(docs): update to use celshast #719)

Community

• Initial version of our AI policy for contribution by @Trenza1ore (docs: add AI policy for contributions #714)
• Ensure the appropriate line ending is enforced w/ .gitattributes & pre-commit by @Trenza1ore (style: ensure the appropriate line ending is enforced for files within the repo #717)

CI and build

• Update license and use PEP 639 license declaration in pyproject.toml by @Trenza1ore (chore: use PEP 639 license declaration in pyproject.toml #718)
• Extend CI to cover macOS & Windows by @Trenza1ore (ci: also run unit tests on windows and macos #725)
• General CI improvements by @mwydmuch (Update publish workflow #710, Bump pyupgrade version to fix precommit for Python 3.14 #712)

Others

• Specify docstring convention for HighwayEnv to be pep257 & minor linting improvements by @Trenza1ore (chore: minor linting improvements #722)

New Contributors

• @teddytennant made their first contribution in fix: prevent silent uint8 overflow of OccupancyGrid observation shape #709
• @AntaresFeng made their first contribution in fix(intersection): prevent in-loop list mutation & removing controlled vehicles in rare cases #721

Full Changelog: v1.12...v1.12.1

---

This discussion was created from the release Bug fixes regarding intersection env & enhancements regarding community contributions.