chore(deps): bump google-auth-oauthlib in /admin_sdk/reseller

Bumps [google-auth-oauthlib](https://github.com/GoogleCloudPlatform/google-auth-library-python-oauthlib) from 0.4.0 to 1.2.1.
- [Release notes](https://github.com/GoogleCloudPlatform/google-auth-library-python-oauthlib/releases)
- [Changelog](https://github.com/googleapis/google-auth-library-python-oauthlib/blob/main/CHANGELOG.md)
- [Commits](googleapis/google-auth-library-python-oauthlib@v0.4.0...v1.2.1)

---
updated-dependencies:
- dependency-name: google-auth-oauthlib
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

admin_sdk/reseller/requirements.txt

@@ -1,3 +1,3 @@
 google-api-python-client==1.7.9
 google-auth-httplib2==0.0.3
-google-auth-oauthlib==0.4.0
+google-auth-oauthlib==1.2.1