build(deps): bump rsa from 3.1.4 to 4.7 in /requirements

Bumps [rsa](https://github.com/sybrenstuvel/python-rsa) from 3.1.4 to 4.7.
- [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-3.1.4...version-4.7)

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

requirements/prod.txt

@@ -1,6 +1,6 @@
 -r base.txt
 
-rsa==3.1.4
+rsa==4.7
 gunicorn==19.7.1
 raven==6.1.0
 boto==2.47.0