check_embedded_chart_code has Python dependencies

Author: minrk

.github/workflows/test.yml

@@ -14,6 +14,9 @@ jobs:
     steps:
       - uses: actions/checkout@v2
 
+      - name: install requirements
+        run: pip install ruamel.yaml
+
       - name: check embedded chart code
         run: ./ci/check_embedded_chart_code.py