Restore playwright; upgrade black

[bensteinberg]

This PR restores playwright to requirements.in, as we need it for functional tests; it also unpins and upgrades black and lets it make some changes.

https://github.com/psf/black/blob/main/CHANGES.md#2430

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 76.89%. Comparing base (ab56c04) to head (6ff3ac7).

Files	Patch %	Lines
web/main/legal_document_sources.py	0.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #2045   +/-   ##
========================================
  Coverage    76.89%   76.89%           
========================================
  Files           60       60           
  Lines         6999     6999           
========================================
  Hits          5382     5382           
  Misses        1617     1617           

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[rebeccacremona]

Hmmm, does this mean the functional tests aren't currently run by Github Actions? Interesting, I didn't realize that.

[bensteinberg]

Hmmm, does this mean the functional tests aren't currently run by Github Actions? Interesting, I didn't realize that.

I think they are running!

[rebeccacremona]

I must be confused. If playwright is necessary for functional tests, and functional tests are run in Github Actions, and we removed playwright in an earlier PR... I would have expected to see the tests fail. Since we didn't... I'm confused.

[bensteinberg]

Could playwright be built in to the runner?