Add a workflow to remove the safe to test label on PR updates.

Author: simonmarty

.github/workflows/pr_sync.yml

@@ -0,0 +1,24 @@
+name: Remove label when new commits are pushed
+
+on:
+  pull_request:
+    types: [synchronize]
+
+jobs:
+  remove-label:
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+
+    steps:
+      - name: Remove label
+        env:
+          LABEL_NAME: safe-to-test
+          OWNER: ${{ github.repository_owner }}
+          REPO: ${{ github.event.pull_request.base.repo.name }}
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+        run: |
+          echo "Removing label '$LABEL_NAME' from PR #$PR_NUMBER on repo $REPO"
+
+      - name: Remove label with gh CLI
+        run: gh api repos/$REPO/issues/$PR_NUMBER/labels/$LABEL_NAME -X DELETE || true