Prepare release v251

[heroku-linguist[bot]]

Commits since the last release:

• Bump rubocop from 1.63.0 to 1.63.4 in the ruby-dependencies group (#1577)
• Build Python 3.10 runtimes for Heroku-24 too (#1579)
• Explicitly install libreadline-dev when building Python runtimes (#1580)
• Add pre-upload Python runtime tests (#1581)
• Explicitly install libdb-dev when building Python runtimes (#1582)
• Bump the ruby-dependencies group with 2 updates (#1584)
• Make Python runtime archive tests more robust (#1585)
• Fix editable mode tests after latest setuptools release (#1586)
• Switch to the GA GitHub Actions ARM runners (#1588)
• Bump rubocop from 1.63.5 to 1.64.1 in the ruby-dependencies group (#1590)
• Add support for Python 3.12.4 (#1591)

For the full diff, see the compare view: https://github.com/heroku/heroku-buildpack-python/compare/v250...main

[edmorley]

$ make publish
Deploy as version: v251 [y/n]? y

Tagging commit c5061734b4490bd5de3b21c919c98de98a3c9d45 with v251... 
Total 0 (delta 0), reused 0 (delta 0), pack-reused 0
To https://github.com/heroku/heroku-buildpack-python
 * [new tag]         v251 -> v251

Publishing to the buildpack registry...
Two-factor code: ********************************************
Publishing buildpack heroku/python... done
Publishing buildpack was successful

 Version Released At              Status    
 ─────── ──────────────────────── ───────── 
 251     2024-06-07T16:07:08.172Z published