gha: Add fetch-depth 1 to actions/checkout

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

@@ -8,6 +8,8 @@ jobs:
 
     steps:
     - uses: actions/checkout@master
+      with:
+        fetch-depth: 1
 
     - name: build
       env:
@@ -20,6 +22,8 @@ jobs:
     runs-on: ubuntu-18.04
     steps:
     - uses: actions/checkout@master
+      with:
+        fetch-depth: 1
     - name: shellcheck
       run: shellcheck ./entrypoint.sh
 
@@ -27,6 +31,8 @@ jobs:
     runs-on: macOS-10.14
     steps:
     - uses: actions/checkout@master
+      with:
+        fetch-depth: 1
     - name: hadolint
       run: |
         brew install hadolint