pr-verify: use env var for passing the PR title

Author: chrischdi

.github/workflows/pr-verify.yaml

@@ -12,6 +12,8 @@ jobs:
       - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # tag=v4.1.7
 
       - name: Check if PR title is valid
+        env:
+          PR_TITLE: ${{ github.event.pull_request.title }}
         run: |
-          ./hack/verify-pr-title.sh "${{ github.event.pull_request.title }}"
+          ./hack/verify-pr-title.sh "${PR_TITLE}"