Add typing stubs for regex package

[jpy-git]

I would like to add stubs for the regex package:
This regex implementation is backwards-compatible with the standard 're' module, but offers additional functionality.

I've found it really useful in a couple projects and it currently doesn't have stubs/typing. It's implementation is similar to to the stdlib re module so will look there for inspiration.

This should help close this issue in the regex repo.

[srittau]

We generally accept stubs for all packages installable via PyPI on modern Python versions.

[jpy-git]

Cool it's available on PyPI so should be fine 👍