label-pull-requests: add `allow_any_match`

[cho-m]

Not sure about naming.

Currently need a way to correctly label PRs when they modify more than one file (e.g. alias, multiple synced formulae, etc).

Particularly for some CI-impacting labels which can be problematic if missing, e.g. long build & CI-build-dependents-from-source for ghc always missing on next major/minor release.

[cho-m]

Still don't know how CI checks work for actions repo.

[Bo98]

It basically doesn't work for forked repos at the moment. I'm still working on how to best handle that - there's not really one global answer here and some actions will be really difficult to properly test without basically faking the whole thing and pretending it works.

You should however have privileges to push to a branch here however and open a non-fork PR.

[chenrui333]

yeah, CI run failure is because of the repo fork issue.

[MikeMcQuaid]

Merging and we can revert if there's issues.