Move up to Fedora 34 defaults

[mulkieran]

• Fix all Fedora 34 test failures:

For each repo with a weekly.yml file:
  * Run it by hand. If all the tests pass, there's nothing to do.
  * Otherwise, make a PR to fix the tests on a Fedora 34 machine

Special note: allow all pylint consider-using-with lints; ones that could be fixed already have been.

• Bump Jenkins environments to Fedora 34

[mulkieran]

There is sort of an already related issue: pylint-dev/pylint#4808. I'll take a look and see if it is related to our cases. EDIT: It is exactly the same. We should mark any remaining consider-using-with lints as false positives.

[mulkieran]

@bgurney-rh Plz bump Jenkins machines and then we can close this issue.

[mulkieran]

Done!