chore: pin github actions to specific SHAs to mitigate supply chain attacks (#442)

.github/workflows/labels.yml

@@ -11,9 +11,9 @@ jobs:
   labels:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
       - name: Set up Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@8d9ed9ac5c53483de85588cdf95a591a75ab9f55 # v5
         with:
           python-version: 3.8
       - name: Install labels