ci: Run pr-check action on reopened PRs (#2390)

Just something I noticed when closing/re-opening the npm audit PR
earlier. The pr-check action doesn't run on re-opened PRs, so you have
to close/reopen, then edit the PR title to trigger all the actions

Author: mattrunyon

.github/workflows/conventional-pr-check.yml

@@ -4,6 +4,7 @@ on:
   pull_request_target:
     types:
       - opened
+      - reopened
       - edited
       - synchronize