diff --git a/.github/workflows/docker-image-ci.yml b/.github/workflows/docker-image-ci.yml
index bcf6f02..4d22c8a 100644
--- a/.github/workflows/docker-image-ci.yml
+++ b/.github/workflows/docker-image-ci.yml
@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-18.04
 
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v1
       with:
         fetch-depth: 1
 
@@ -30,7 +30,7 @@ jobs:
   shellcheck:
     runs-on: ubuntu-18.04
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v1
       with:
         fetch-depth: 1
     - name: shellcheck
@@ -39,7 +39,7 @@ jobs:
   hadolint:
     runs-on: macos-latest
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v1
       with:
         fetch-depth: 1
     - run: brew install hadolint