Prepare release v325

[heroku-linguist]

Commits since the last release:

• Sunset implicit setup.py support (Sunset implicit setup.py support #1992)
• Error when multiple package manager files are found (Error when multiple package manager files are found #1993)
• Bump uv from 0.9.14 to 0.9.17 (Bump uv from 0.9.14 to 0.9.17 #1995)

For the full diff, see the compare view:
v324...main

[edmorley]

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

- The build now errors if the files for multiple package managers are found. This replaces the warning displayed since November 2024. ([#1993](https://github.com/heroku/heroku-buildpack-python/pull/1993))
- Sunset the previously deprecated support for falling back to installing dependencies from a `setup.py` file if no Python package manager files were found. ([#1992](https://github.com/heroku/heroku-buildpack-python/pull/1992))
- Updated uv from 0.9.14 to 0.9.17. ([#1995](https://github.com/heroku/heroku-buildpack-python/pull/1995))

Deploy as v325 [y/n]? y

Creating GitHub release...
https://github.com/heroku/heroku-buildpack-python/releases/tag/v325

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

 Version Released At              Status    
 ─────── ──────────────────────── ───────── 
 325     2025-12-10T13:46:57.255Z published