Add automatic assignment to the internal-sites team

[Urgau]

As discussed in #3865 (comment), let's add us as the reviewer team for "not-rfc" changes in this repo.

r? @jieyouxu

[jieyouxu]

Makes sense to me as the maintenance team, thanks

[jieyouxu]

I was going to say "I wonder if we can auto-apply not-rfc label for PRs not modifying text/" (as a follow-up)... I can't remember, can label trigger files use negative path filters? If triagebot can't handle that, it's fine, not worth the impl complexity to support IMO.

[Urgau]

can label trigger files use negative path filters?

No, that's not supported currently, but we could do the same thing as here and manually list the files and directory, it wouldn't be much.

[jieyouxu]

but we could do the same thing as here and manually list the files and directory, it wouldn't be much

Ah the counter-example I had in mind was you could have both RFC changes and non-RFC changes in the same PR, then not-rfc would be inaccurate. But edge case IMO. Anyway, just a musing, not for this PR.