diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 454fe0fbe..d6d072eb4 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -22,7 +22,7 @@ jobs:
     timeout-minutes: 5
     steps:
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v2.3.4
     - name: Setup Python 3.9
       uses: actions/setup-python@v2.2.2
       with:
@@ -80,7 +80,7 @@ jobs:
     timeout-minutes: 15
     steps:
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v2.3.4
     - name: Setup Python ${{ matrix.pyver }}
       uses: actions/setup-python@v2.2.2
       with:
@@ -133,7 +133,7 @@ jobs:
     needs: pre-deploy
     steps:
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v2.3.4
     - name: Setup Python 3.8
       uses: actions/setup-python@v2.2.2
       with:
@@ -161,7 +161,7 @@ jobs:
     needs: pre-deploy
     steps:
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v2.3.4
     - name: Set up QEMU
       id: qemu
       uses: docker/setup-qemu-action@v1
@@ -200,7 +200,7 @@ jobs:
     needs: pre-deploy
     steps:
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v2.3.4
     - name: Setup Python 3.8
       uses: actions/setup-python@v2.2.2
       with: