Remove deprecated extra gui_qt from setup.cfg

[user202729]

According to pypa/setuptools#4862 , specifying extra for entrypoint is deprecated. And as I explained there, it breaks some features (in particular if that is used then gui_qt no longer work on my machine).

The simplest way seems to be just remove the extra specification.

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[mkrnr]

LGTM 👍

Also did a quick test on the PySide6 branch and removing this didn't seem to have any impact.

Feel free to merge the PR.

[tsprlng]

This change seems to break the build on MacOS (at least locally for me), causing the check_requirements step at the end of osx/make_app.sh to fail with pkg_resources.UnknownExtra: plover 4.0.0 has no such extra feature 'gui_qt' -- not sure why though. Probably it's related to the MacOS builds pinning a 3.9 version of Python when assembling the app?

[tsprlng]

(Is this PySide6 branch up anywhere, out of interest?)

[user202729]

Understandable, given Plover uses quite a lot of pkg_resources sanity check internally. (Sometimes the sanity check is a bit too strict though. This one probably qualifies.)

See also #1703

Given the above, and the fact that dependency on entry point itself is going to be deprecated, it's probably sufficient if we just remove the relevant check.

(The PySide6 branch is at #1601 . )