diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index dd5c44f..b6a1bb9 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -10,7 +10,7 @@
     runs-on: ubuntu-latest
     steps:
       - name: Checkout master
-        uses: actions/checkout@v1
+        uses: actions/checkout@v2.3.4
 
       - name: Deploy docs
         uses: mhausenblas/mkdocs-deploy-gh-pages@v1.16