[CI] Ignore sockets from artifacts upload

[thenets]

Some pipelines are failing on test step due to an attempt to upload socket files.

Example:
https://github.com/ansible/receptor/runs/4287669792?check_suite_focus=true

cc: @shanemcd

[shanemcd]

@thenets is this still a problem?

[thenets]

@shanemcd I don't know. I have this issue here for the next week:

• Add plugin pytest-github to the receptorctl test suite #495

I can do it and at the same time check if this still happening.