Enforce ruff/pyupgrade rules (UP)

[DimitriPapadopoulos]

As part of repo-review suggestions:

https://learn.scientific-python.org/development/guides/repo-review/?repo=pypa%2Fpipx&branch=main

[notatallshaw]

FWIW, enabling pyupgrade rules by default was discussed and the sentiment appeared to be to run it on an ad-hoc basis not to enforce it: #11944 (comment)

[DimitriPapadopoulos]

FWIW, enabling pyupgrade rules by default was discussed and the sentiment appeared to be to run it on an ad-hoc basis not to enforce it: #11944 (comment)

Would you like me to remove UP from the selected ruff rules?

[notatallshaw]

Would you like me to remove UP from the selected ruff rules?

I'm personally supportivel of UP being a selected rule set, and turning off any particular rules if they're found to be problematic. But pip maintainers may have different opinions (as linked).

[pradyunsg]

Let's do this. We can come back can remove things if we want to.