Prepare release v273 (#1730)

Co-authored-by: heroku-linguist[bot] <136119646+heroku-linguist[bot]@users.noreply.github.com>

Author: heroku-linguist[bot]

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## [Unreleased]
 
+
+## [v273] - 2025-01-03
+
 - Added more Python project related file and directory names to the list recognised by buildpack detection. ([#1729](https://github.com/heroku/heroku-buildpack-python/pull/1729))
 - Improved the file listing in the error messages shown when buildpack detection fails or when no Python package manager files are found. ([#1728](https://github.com/heroku/heroku-buildpack-python/pull/1728))
 
@@ -1137,7 +1140,8 @@ Default Python is now latest 2.7.10. Updated pip and Distribute.
 - Setuptools updated to v16.0
 - pip updated to v7.0.1
 
-[unreleased]: https://github.com/heroku/heroku-buildpack-python/compare/v272...main
+[unreleased]: https://github.com/heroku/heroku-buildpack-python/compare/v273...main
+[v273]: https://github.com/heroku/heroku-buildpack-python/compare/v272...v273
 [v272]: https://github.com/heroku/heroku-buildpack-python/compare/v271...v272
 [v271]: https://github.com/heroku/heroku-buildpack-python/compare/v270...v271
 [v270]: https://github.com/heroku/heroku-buildpack-python/compare/v269...v270