Use commit instead of version for github actions.

.github/workflows/sync-sas-strings.yml

@@ -12,9 +12,9 @@ jobs:
     if: ${{ github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name == 'element-hq/element-x-android' }}
     # No concurrency required, runs every time on a schedule.
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       - name: Set up Python 3.12
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: 3.14
       - name: Install Prerequisite dependencies