chore(deps): bump google-auth-httplib2 from 0.3.0 to 0.3.1 in /backend

Bumps [google-auth-httplib2](https://github.com/googleapis/google-cloud-python) from 0.3.0 to 0.3.1.
- [Release notes](https://github.com/googleapis/google-cloud-python/releases)
- [Changelog](https://github.com/googleapis/google-cloud-python/blob/main/CHANGELOG.md)
- [Commits](https://github.com/googleapis/google-cloud-python/compare/google-auth-httplib2-v0.3.0...google-auth-httplib2-v0.3.1)

---
updated-dependencies:
- dependency-name: google-auth-httplib2
  dependency-version: 0.3.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

backend/requirements.txt

@@ -31,7 +31,7 @@ email-validator==2.1.0.post1
 google-api-python-client==2.193.0
 google-auth==2.49.1
 google-auth-oauthlib==1.3.1
-google-auth-httplib2==0.3.0
+google-auth-httplib2==0.3.1
 
 # Job Queue & Cache
 celery==5.6.3