Prepare release v339

[heroku-linguist]

Commits since the last release:

• Update test fixture after change in S3 bucket permissions (Update test fixture after change in S3 bucket permissions #2048)
• Bump uv from 0.10.7 to 0.10.9 (Bump uv from 0.10.7 to 0.10.9 #2049)
• Download uv from releases.astral.sh instead of GitHub releases (Download uv from releases.astral.sh instead of GitHub releases #2050)
• Add more misspellings to the .python-version filename check (Add more misspellings to the .python-version filename check #2051)

For the full diff, see the compare view:
v338...main

[edmorley]

$ make publish
Checking environment...
Checking buildpack versions in sync...
Extracting changelog entry for this release...

- Updated uv from 0.10.7 to 0.10.9. ([#2049](https://github.com/heroku/heroku-buildpack-python/pull/2049))
- Switched to downloading uv from `releases.astral.sh` instead of GitHub releases. ([#2050](https://github.com/heroku/heroku-buildpack-python/pull/2050))
- Updated the check for misspelled `.python-version` files with additional misspellings seen in the wild. ([#2051](https://github.com/heroku/heroku-buildpack-python/pull/2051))

Deploy as v339 [y/n]? y

Creating GitHub release...
https://github.com/heroku/heroku-buildpack-python/releases/tag/v339

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

 Version Released At              Status    
 ─────── ──────────────────────── ───────── 
 339     2026-03-13T12:53:55.770Z published