retrigger (at least) the cargo-vet-check CI in response to cargo-vet-certify pushes

Github has a safety valve against workflows-triggering-workflows that extends to commits created by workflows. This is Good because it prevents infinite loops and infinite CPU waste.

However we specifically *do* want this, especially since cargo-vet-certify is only triggered by humans, so there's no loop.

It seems doing a git commit "properly" "with oauth" may bypass this safety valve: https://stackoverflow.com/questions/72421030/merge-by-github-action-does-not-trigger-ci-that-listen-by-branch