infra: ensure template alignment across branches

.github/workflows/template-check.yml

@@ -59,3 +59,45 @@ jobs:
               exit 1
             fi
           done
+
+  infra-template-master-match-check:
+    runs-on: ubuntu-20.04
+    name: Compare templates files with master branch
+    if: github.event.pull_request.base.ref != 'master'
+
+    steps:
+      - name: Clone Anaconda repository
+        uses: actions/checkout@v3
+        with:
+          # TODO: Are we able to remove ref, fetch-depth and Rebase task? Seems that the checkout
+          # without ref is doing the rebase for us.
+          # otherwise we are testing target branch instead of the PR branch (see pull_request_target trigger)
+          ref: ${{ github.event.pull_request.head.sha }}
+          fetch-depth: 0
+
+      - name: Rebase to current
+        run: |
+          git config user.name github-actions
+          git config user.email [email protected]
+          git log --oneline -1 origin/${{ github.event.pull_request.base.ref }}
+          git rebase origin/${{ github.event.pull_request.base.ref }}
+
+      - name: Check if all changed template files are matching master branch
+        run: |
+          changed_template_files_in_pr=$(git diff --diff-filter=M --name-only origin/${{ github.event.pull_request.base.ref }} *.yml.j2)
+          if [ -z "$changed_template_files_in_pr" ]; then
+            echo "----- No template files changed -----"
+
+            exit 0
+          fi
+
+          changed_files=$(git diff --diff-filter=M --name-only origin/master *.yml.j2)
+
+          if [ -n "$changed_files" ]; then
+            # print for debugging
+            echo "----- Template files differ with mater branch -----"
+            echo "$changed_files"
+            echo "-------------------------"
+
+            exit 1
+          fi