Bump babel from 2.10.1 to 2.15.0 in /requirements

Bumps [babel](https://github.com/python-babel/babel) from 2.10.1 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@v2.10.1...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]>

requirements/common.txt

@@ -1,4 +1,4 @@
-Babel==2.10.1
+Babel==2.15.0
 django-contact-form==5.0.1
 django-countries==7.6.1
 django-hosts==5.1