Mention core-workflow mailing list / repo

[Mariatta]

It should worth mentioning in the devguide somewhere that there's core-workflow mailing list and core-workflow repo.

[ncoghlan]

New entries in https://docs.python.org/devguide/communication.html would probably make sense for that. That page is also likely a reasonable place to list "Additional Repositories" (for core-workflow, the benchmark suite, and probably the issue tracker).

[matrixise]

@ncoghlan issue tracker ? b.p.o or the issue tracker of the infra ?

[matrixise]

Hi @ncoghlan and @Mariatta

I just created the PR for this issue, need your reviews.

Thank you

[matrixise]

please @ncoghlan and @Mariatta, could you review this PR ?

Thank you

[Mariatta]

Closed in #220

[Mariatta]

Thanks for the PR @matrixise 🌮