diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 9128b16..7e56411 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -5,7 +5,7 @@ jobs:
     runs-on: ubuntu-20.04
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4
 
       - name: Set up Python
         uses: actions/setup-python@v2