Bump python-dotenv from 0.20.0 to 0.21.0

Bumps [python-dotenv](https://github.com/theskumar/python-dotenv) from 0.20.0 to 0.21.0.
- [Release notes](https://github.com/theskumar/python-dotenv/releases)
- [Changelog](https://github.com/theskumar/python-dotenv/blob/main/CHANGELOG.md)
- [Commits](theskumar/python-dotenv@v0.20.0...v0.21.0)

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

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

Author: dependabot[bot]

requirements.txt

@@ -1,3 +1,3 @@
 github3.py==3.2.0
-python-dotenv==0.20.0
+python-dotenv==0.21.0
 repo-activity-score==0.0.4