Use shell to detect file changes in build dir

Replace dorny/paths-filter action with a custom shell script to
determine if there are changes in the following dirs:

* 'images/docker/cbdb/build/rocky8/'
* 'images/docker/cbdb/build/rocky9/'

See: apache#20

Author: tuhaihe

.github/workflows/docker-cbdb-test-containers.yml

@@ -80,13 +80,26 @@ jobs:
       # Determine if the current platform's files have changed
       - name: Determine if platform changed
         id: platform-filter
-        uses: dorny/paths-filter@v3
-        with:
-          filters: |
-            rocky8:
-              - 'images/docker/cbdb/test/rocky8/**'
-            rocky9:
-              - 'images/docker/cbdb/test/rocky9/**'
+        run: |
+          # Check Rocky 8 changes
+          if git diff --name-only ${{ github.event.before }} ${{ github.event.after }} | grep -q "^images/docker/cbdb/build/rocky8/"; then
+            echo "rocky8=true" >> $GITHUB_OUTPUT
+          else
+            echo "rocky8=false" >> $GITHUB_OUTPUT
+          fi
+
+          # Check Rocky 9 changes
+          if git diff --name-only ${{ github.event.before }} ${{ github.event.after }} | grep -q "^images/docker/cbdb/build/rocky9/"; then
+            echo "rocky9=true" >> $GITHUB_OUTPUT
+          else
+            echo "rocky9=false" >> $GITHUB_OUTPUT
+          fi
+
+          # For workflow_dispatch events, always return true
+          if [[ "${{ github.event_name }}" == "workflow_dispatch" ]]; then
+            echo "rocky8=true" >> $GITHUB_OUTPUT
+            echo "rocky9=true" >> $GITHUB_OUTPUT
+          fi
 
       # Skip if no changes for current platform
       - name: Skip if not relevant