regex: add support for RegexFlag class

[rrthomas]

No description provided.

[srittau]

Thanks!

[AlexWaygood]

The failing stub-uploader test is nothing to worry about -- the same test is failing on the stub-uploader master branch:

• https://github.com/typeshed-internal/stub_uploader/actions/runs/3226338425/jobs/5279737323
• Allow external dependencies typeshed-internal/stub_uploader#61 (comment)

(Cc. @hauntsaninja)

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉

[srittau]

The test failure seems unrelated, probably caused by typeshed-internal/stub_uploader#61.

[rrthomas]

Thanks for merging this PR, @srittau! As I understand it, the corresponding type-stubs package (here, regex-types) should be automatically released after the change, but it has not been. Is some other change (like a version bump) needed?

[srittau]

Indeed. Actually, this CI run claims that it was uploaded, but it wasn't: https://github.com/typeshed-internal/stub_uploader/actions/runs/3228142124/jobs/5283851894

I'm investigating.

[srittau]

typeshed-internal/stub_uploader#68

[JelleZijlstra]

I manually triggered a new version of regex and it somehow succeeded.