tests: refactor tests to ignore readme generation for Dockerfile changes

Ideally we can trigger a readme update on merge in the future. For now, this will work well.

.github/workflows/ci.yml

@@ -21,6 +21,9 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+
       - uses: actions/setup-python@v2
         with:
           python-version: '3.7.x'
@@ -30,6 +33,11 @@ jobs:
       - run: sudo sysctl -w vm.max_map_count=262144
 
       - run: |
+          git fetch -q origin master
+          changed=$(git --no-pager diff --name-only $GITHUB_SHA..origin/master)
+          if [ $changed = "Dockerfile" ]; then
+            echo "Please run 'make generate' to update the image version in the README.md"
+          else
             make generate
             if ! git diff --quiet README.md; then
               echo "Please run 'make generate'"
@@ -37,6 +45,7 @@ jobs:
               git --no-pager diff README.md
               exit 1
             fi
+          fi
 
       - run: make test
 
@@ -56,6 +65,9 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+
       - uses: actions/setup-python@v2
         with:
           python-version: '3.7.x'
@@ -65,13 +77,19 @@ jobs:
       - run: sudo sysctl -w vm.max_map_count=262144
 
       - run: |
+          git fetch -q origin master
+          changed=$(git --no-pager diff --name-only $GITHUB_SHA..origin/master)
+          if [ $changed = "Dockerfile" ]; then
+            echo "Please run 'make generate' to update the image version in the README.md"
+          else
             make generate
             if ! git diff --quiet README.md; then
-            echo "Please run `make generate`"
+              echo "Please run 'make generate'"
               git status --short
               git --no-pager diff README.md
               exit 1
             fi
+          fi
 
       - run: make test