Add support for Python 3.12.13, 3.11.15 and 3.10.20 (#521)

Release announcement:
https://blog.python.org/2026/03/python-31213-31115-31020/

Changelogs:
https://docs.python.org/release/3.12.13/whatsnew/changelog.html#python-3-12-13-final
https://docs.python.org/release/3.11.15/whatsnew/changelog.html#python-3-11-15-final
https://docs.python.org/release/3.10.20/whatsnew/changelog.html#python-3-10-20-final

Binary builds:
https://github.com/heroku/heroku-buildpack-python/actions/runs/22639900939
https://github.com/heroku/heroku-buildpack-python/actions/runs/22639906742
https://github.com/heroku/heroku-buildpack-python/actions/runs/22639923074

GUS-W-21433847.

Author: edmorley

CHANGELOG.md

@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+
+- The Python 3.12 version alias now resolves to Python 3.12.13. ([#521](https://github.com/heroku/buildpacks-python/pull/521))
+- The Python 3.11 version alias now resolves to Python 3.11.15. ([#521](https://github.com/heroku/buildpacks-python/pull/521))
+- The Python 3.10 version alias now resolves to Python 3.10.20. ([#521](https://github.com/heroku/buildpacks-python/pull/521))
+
 ## [6.0.0] - 2026-03-03
 
 ### Changed

src/python_version.rs

@@ -21,9 +21,9 @@ pub(crate) const NEWEST_SUPPORTED_PYTHON_3_MINOR_VERSION: u16 = 14;
 pub(crate) const NEXT_UNRELEASED_PYTHON_3_MINOR_VERSION: u16 =
     NEWEST_SUPPORTED_PYTHON_3_MINOR_VERSION + 1;
 
-pub(crate) const LATEST_PYTHON_3_10: PythonVersion = PythonVersion::new(3, 10, 19);
-pub(crate) const LATEST_PYTHON_3_11: PythonVersion = PythonVersion::new(3, 11, 14);
-pub(crate) const LATEST_PYTHON_3_12: PythonVersion = PythonVersion::new(3, 12, 12);
+pub(crate) const LATEST_PYTHON_3_10: PythonVersion = PythonVersion::new(3, 10, 20);
+pub(crate) const LATEST_PYTHON_3_11: PythonVersion = PythonVersion::new(3, 11, 15);
+pub(crate) const LATEST_PYTHON_3_12: PythonVersion = PythonVersion::new(3, 12, 13);
 pub(crate) const LATEST_PYTHON_3_13: PythonVersion = PythonVersion::new(3, 13, 12);
 pub(crate) const LATEST_PYTHON_3_14: PythonVersion = PythonVersion::new(3, 14, 3);