pypi: support updating resources for git clones

[branchvincent]

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This teaches brew update-python-resources how to handle a formula with a git url, like arcade-learning-environment.

Before:

$ brew update-python-resources arcade-learning-environment
Error: Unable to determine metadata for "https://github.com/mgbellemare/Arcade-Learning-Environment.git" because of a failure when running
`/opt/homebrew/opt/[email protected]/bin/python3 -m pip install -q --no-deps --dry-run --ignore-installed --report /dev/stdout https://github.com/mgbellemare/Arcade-Learning-Environment.git`.
Please report this issue:
  https://docs.brew.sh/Troubleshooting

After:

$ brew update-python-resources arcade-learning-environment
==> Retrieving PyPI dependencies for "git+https://github.com/mgbellemare/[email protected]"...
==> Getting PyPI info for "importlib-resources==6.0.0"
==> Getting PyPI info for "numpy==1.25.2"
==> Updating resource blocks

[apainintheneck]

This makes sense to me.

As a side note, it looks like this isn't necessarily well described in the docs. The tag: and revision: options are only mentioned under the Unstable Versions (head) section which seems to imply that head blocks and these url options are somehow related even though you can use them in stable blocks as well. Maybe it'd be a good idea to add a specific section that talks about url options. Obviously this is completely unrelated to this PR. It just made me think of that.

[MikeMcQuaid]

Maybe it'd be a good idea to add a specific section that talks about url options.

Good idea 👍🏻

[MikeMcQuaid]

Thanks again @branchvincent!

[drewfish]

BTW this broke a tap I was using for company-internal tools. (Yep, I know that's not a goal of homebrew, so I'm kinda on my own with that.) I was doing:

  url "git+ssh://[email protected]/mycompany/mypythontool.git",
     using:    :git,
     tag:      "1.2.3"

I was able to fix it by removing the git+ prefix. An example in Python-for-Formula-Authors would be helpful, even just a link to a formula. Oh nevermind, I see that the "Formula Cookbook" has been revised, thanks!