Bump babel from 2.14.0 to 2.15.0

Bumps [babel](https://github.com/python-babel/babel) from 2.14.0 to 2.15.0.
- [Release notes](https://github.com/python-babel/babel/releases)
- [Changelog](https://github.com/python-babel/babel/blob/master/CHANGES.rst)
- [Commits](python-babel/babel@v2.14.0...v2.15.0)

---
updated-dependencies:
- dependency-name: babel
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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