Fixes #33766 - Support Pulpcore 3.15

[ekohl]

No description provided.

[ekohl]

I hear 3.16 is being worked on as well, but 3.15 is built today and is SCL'ed. On EL8 it also uses modules for Python 3.8. Having this PR allows us to verify we actually work.

[ekohl]

And will be removed in 3.16.

[ekohl]

Looks like RQ is broken on EL7 with 3.15 but EL8 does pass. Perhaps some SCL issue.

[ehelms]

You could go either way that this broken rq depending on how we think about exposing the command line tool. The tests use rq directly to inspect the state of the workers and that command does not exist outside the SCL context (e.g. https://github.com/theforeman/puppet-pulpcore/blob/master/spec/acceptance/enable_new_tasking_system_spec.rb#L65).

So we either update packaging to make an SCL aware rq or just update our tests to enable the SCL context on EL7. Or we stop testing RQ on EL7 knowing it's gone in 3.16.

[ekohl]

Or we stop testing RQ on EL7 knowing it's gone in 3.16.

I'm leaning to the latter. We can even take the version into account here.

[evgeni]

The RQ issue is simple to fix: #240

[ekohl]

This is now green. With the notes in README I would consider this a backwards compatible enhancement.