ci: shared action for "create bug on post-PR failures"

[coryan]

At least librarian, google-cloud-rust, and now google-cloud-swift have a GitHub action to create issues if a push (post-PR) build fails. They are all similar, cut&pasted from each other, the one in librarian is "almost" an action we could reuse.

Credit to @chingor13 I just continued the cut&paste tradition.

[zhumin8]

Some of our language repos are already using the librarian action, e.g., https://github.com/googleapis/google-cloud-php/blob/320cc567ed185c483d73ac998f529b9aaa244d5e/.github/workflows/generation-check.yaml#L43-L53, https://github.com/googleapis/google-cloud-java/blob/a16f0489f8da34e2d460760d8c0167ae3a7d905a/.github/workflows/librarian_generation_check.yaml#L102-L112
(Some don't, we should probably update).

What is the gap between this and use case for google-cloud-rust and google-cloud-swift?