ci: Skip frontend tests for Dependabot PRs

src/bin/plugins/lib/frontend-tests.yml

@@ -9,6 +9,17 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+      -
+        name: Fail if Dependabot
+        if: github.actor == 'dependabot[bot]'
+        run: |
+          cat <<EOF >&2
+          Frontend tests skipped because Dependabot can't access secrets.
+          Manually re-run the jobs to run the frontend tests.
+          For more information, see:
+          https://github.blog/changelog/2021-02-19-github-actions-workflows-triggered-by-dependabot-prs-will-run-with-read-only-permissions/
+          EOF
+          exit 1
       -
         name: Generate Sauce Labs strings
         id: sauce_strings