Bump tox from 3.25.0 to 4.15.0

Bumps [tox](https://github.com/tox-dev/tox) from 3.25.0 to 4.15.0.
- [Release notes](https://github.com/tox-dev/tox/releases)
- [Changelog](https://github.com/tox-dev/tox/blob/main/docs/changelog.rst)
- [Commits](tox-dev/tox@3.25.0...4.15.0)

---
updated-dependencies:
- dependency-name: tox
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

requirements-dev.txt

@@ -6,7 +6,7 @@ check-manifest==0.49
 flake8==7.0.0
 pytest==8.1.1
 Sphinx==4.3.2
-tox==3.25.0
+tox==4.15.0
 tox-gh-actions==2.9.1
 twine==4.0.2
 wheel==0.40.0