Checkout submodules with --depth=0 (#450)

Author: wata727

.github/workflows/generated_code_checks.yml

@@ -8,8 +8,8 @@ jobs:
     steps:
     - name: Checkout
       uses: actions/checkout@v3
-      with:
-        submodules: true
+    - name: Checkout submodules
+    - run: git submodule update --init --depth=0
     - name: Set up Go
       uses: actions/setup-go@v3
       with:

.github/workflows/maintenance.yaml

@@ -9,8 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
-        with:
-          submodules: true
+      - run: git submodule update --init --depth=0
       - uses: actions/setup-go@v3
         with:
           go-version-file: 'go.mod'