update: update rsa requirement from ~=4.7.2 to ~=4.8

Updates the requirements on [rsa](https://github.com/sybrenstuvel/python-rsa) to permit the latest version.
- [Release notes](https://github.com/sybrenstuvel/python-rsa/releases)
- [Changelog](https://github.com/sybrenstuvel/python-rsa/blob/main/CHANGELOG.md)
- [Commits](sybrenstuvel/python-rsa@version-4.7.2...version-4.8)

---
updated-dependencies:
- dependency-name: rsa
  dependency-type: direct:production
...

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

requirements.txt

@@ -11,4 +11,4 @@ pytz~=2022.1
 PyYAML~=6.0
 requests~=2.27.1
 rfc3339-validator~=0.1.4
-rsa~=4.7.2
+rsa~=4.8