Update pr-close-signal.yaml

Author: jt14den

.github/workflows/pr-close-signal.yaml

@@ -16,7 +16,7 @@ jobs:
           mkdir -p ./pr
           printf ${{ github.event.number }} > ./pr/NUM
       - name: Upload Diff
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: pr
           path: ./pr