[Github] Allow Premerge to use issue-write workflow

We want the premerge advisor to write out comments, and we need the
issue-write workflow to trigger on it in order for this to work. Landing
this before the rest of llvm#166609 to enable testing that given this needs
to be in repo due to permissions issues.

Author: boomanaiden154

.github/workflows/issue-write.yml

@@ -7,6 +7,7 @@ on:
       - "Check for private emails used in PRs"
       - "PR Request Release Note"
       - "Code lint"
+      - "CI Checks"
     types:
       - completed