Prepare release v315

[heroku-linguist]

Commits since the last release:

• Update Dependabot config for Docker (Update Dependabot config for Docker #1936)
• Remove redundant internal error handling for venv creation (Remove redundant internal error handling for venv creation #1937)
• Bump sigstore/cosign/cosign from v2.6.1 to v3.0.2 in /builds (Bump sigstore/cosign/cosign from v2.6.1 to v3.0.2 in /builds #1938)
• Stop using a global warnings log file (Stop using a global warnings log file #1939)
• Clean up the install pip step (Clean up the install pip step #1940)
• Pin Poetry's dulwich version (Pin Poetry's dulwich version #1943)
• Bump the ruby-dependencies group across 1 directory with 2 updates (Bump the ruby-dependencies group across 1 directory with 2 updates #1944)
• Bump uv from 0.8.23 to 0.9.4 (Bump uv from 0.8.23 to 0.9.4 #1942)
• Bump uv from 0.9.4 to 0.9.5 in /requirements (Bump uv from 0.9.4 to 0.9.5 in /requirements #1945)

For the full diff, see the compare view:
v314...main

[edmorley]

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

- Updated uv from 0.8.23 to 0.9.5. ([#1942](https://github.com/heroku/heroku-buildpack-python/pull/1942) and [#1945](https://github.com/heroku/heroku-buildpack-python/pull/1945))
- Pinned `dulwich` version when using Poetry to work around an incompatibility with Python <3.9.2. ([#1943](https://github.com/heroku/heroku-buildpack-python/pull/1943))
- Removed redundant internal error handling for venv creation. ([#1937](https://github.com/heroku/heroku-buildpack-python/pull/1937))

Deploy as v315 [y/n]? y

Creating GitHub release...
https://github.com/heroku/heroku-buildpack-python/releases/tag/v315

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

 Version Released At              Status    
 ─────── ──────────────────────── ───────── 
 315     2025-10-22T09:17:19.015Z published