To optimize Docker image size.

.github/workflows/push_image.yml

@@ -10,6 +10,9 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
       - name: Set up Go
         uses: actions/setup-go@v5
         with:
@@ -18,9 +21,6 @@ jobs:
       - name: Build certimate
         run: go build -o certimate
 
-      - name: Checkout code
-        uses: actions/checkout@v4
-
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3