diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 621d0af..810dfc9 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -17,7 +17,7 @@ jobs:
         ruby: [jruby, truffleruby, 2.5, 2.6, 2.7, '3.0', head]
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.4
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}