chore(deps): bump requests from 2.27.1 to 2.28.0 (#317)

Bumps [requests](https://github.com/psf/requests) from 2.27.1 to 2.28.0.
- [Release notes](https://github.com/psf/requests/releases)
- [Changelog](https://github.com/psf/requests/blob/main/HISTORY.md)
- [Commits](psf/requests@v2.27.1...v2.28.0)

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

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Radoslav Dimitrov <dimitrovr@vmware.com>

requirements-test.txt

@@ -1,5 +1,5 @@
 iso8601==1.0.2
-requests==2.27.1
+requests==2.28.0
 securesystemslib==0.21.0
 six==1.16.0
 tuf==0.20.0