Pin test ci actions to hashes.

Author: Sancus

.github/workflows/ci.yml

@@ -24,9 +24,9 @@ jobs:
             os: windows-latest
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8  # v5.0.0
 
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@e797f83bcb11b83ae66e0230d6156d7c80228e7c  # v6.0.0
         with:
           python-version: ${{ matrix.python }}
           cache: pip