Allow testing building crowd_anki/dist when Pipfile.lock is changed

[aplaice]

The uploaded artifact is currently unused.

Fix #182.

We check for changes to both Pipfile and Pipfile.lock to avoid stale a Pipfile.lock.

This will result in some false positive runs of this workflow, when we've, say, added a new script to Pipfile, without changing dependencies.

We will also have false positives when only dev dependencies have been updated.

[aplaice]

Ugh, that didn't work (see:

https://github.com/Stvad/CrowdAnki/actions/runs/5040054106/jobs/9038569945?pr=194 )

(Process substitution (<()) issues?)