Install gvsbuild with pip

[danyeaw]

gvsbuild is now published to PyPI. This PR replaces checking out gvsbuild from source with the published version.

PR Checklist

Please check if your PR fulfills the following requirements:

• [X] I have read, and I am following the Contributor guide
• [X] I have read, and I understand the Code of Conduct

PR Type

What kind of change does this PR introduce?

• [ ] Bug fix
• [ ] Feature
• [X] Chore (refactoring, formatting, local variables, other cleanup)
• [ ] Documentation content changes

What is the current behavior?

Update git hash to update the gvsbuild version

Issue Number: N/A

What is the new behavior?

Bump the version using the published version.

Does this PR introduce a breaking change?

• [ ] Yes
• [X] No

Other information

[amolenaar]

This is really cool. I hope it paves the way for other GTK/GNOME projects to publish their stuff for Windows as well.

[danyeaw]

Thanks for the help @amolenaar :+1: