Bump version and update change log for 1.4.0

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1.4.0 is the first major version supporting enumerations in friendly modules.

The names that were used as aliases for c_int within friendly modules will now be used as the names of enumeration types.

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I've noticed that AppVeyor is not being triggered when I submit a PR.
I will add automated tests using GitHub Actions.
The workflow that will be executed is replicated the same as what was being done with AppVeyor.

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One of the tests that was not skipped in AppVeyor was skipped in GitHub Actions.

test_relpath (test_client.Test_GetModule) ... skipped 'This depends on typelib and test module are in same drive'

comtypes/comtypes/test/test_client.py

Lines 24 to 32 in 0d43d18

	@ut.skipUnless(
	os.path.splitdrive(Scripting.typelib_path)[0]
	== os.path.splitdrive(__file__)[0],
	"This depends on typelib and test module are in same drive",
	)
	def test_relpath(self):
	relpath = os.path.relpath(Scripting.typelib_path, __file__)
	mod = comtypes.client.GetModule(relpath)
	self.assertIs(mod, Scripting)

This is because scrrun.dll, which was on the C drive in the AppVeyor environment, is on a different drive in the GHA environment.
In my local environment, both comtypes and scrrun.dll are on the C drive, so the test is not skipped and passes.