Update checkout workflow.

.github/workflows/push-docker-image.yml

@@ -13,7 +13,7 @@ jobs:
   push-image-to-docker-hub:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           submodules: recursive
 

.github/workflows/push-test-image.yml

@@ -13,7 +13,7 @@ jobs:
   push-image-to-docker-hub:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           submodules: recursive