ci: checkout code

Author: cpcloud

.github/workflows/ci.yml

@@ -37,6 +37,8 @@ jobs:
     outputs:
       skip: ${{ steps.get-should-skip.outputs.should-skip }}
     steps:
+      - name: Checkout repository
+        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8  # v5.0.0
       - name: Compute whether to skip builds and tests
         id: get-should-skip
         env: