Fix Windows Packaging Fails for Missing Files

[danyeaw]

PyInstaller was unable to find the tinycss2/VERSION file.
Adds two PyInstaller hooks to collect the data files. These hooks can be removed once I get them in to a released version of https://github.com/pyinstaller/pyinstaller-hooks-contrib.

PR Checklist

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• I have read, and am following the Contributer guide
• I have read and understand the Code of Conduct

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Documentation content changes

What is the current behavior?

Gaphor fails to launch after installed in Windows.

Issue Number: N/A

What is the new behavior?

Gaphor launches again 🎉

Does this PR introduce a breaking change?

• Yes
• No

Other information

[amolenaar]

We do not use cssselect2 anymore. I think we do not need a hook for that one.

[amolenaar]

Nice change. No need for cssselect2, though. It's not used.

[sourcery-ai]

Sourcery Code Quality Report (beta)

This PR has an average code quality of 9.80 out of 10

Quality metrics	Before	After	Change
Complexity		0.00
Method Length		8.00
Quality	****	9.80	****

Other metrics	Before	After	Change
Lines		5

Changed files	Quality Before	Quality After	Quality Change
win-installer/hooks/hook-tinycss2.py		9.80

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