open manifest test in CI when dockerfile changed (#985)

Signed-off-by: chensuyue <suyue.chen@intel.com>

Author: chensuyue

.github/workflows/pr-manifest-e2e.yml

@@ -8,6 +8,8 @@ on:
     branches: ["main", "*rc"]
     types: [opened, reopened, ready_for_review, synchronize] # added `ready_for_review` since draft is skipped
     paths:
+      - "**/Dockerfile**"
+      - "**.py"
       - "**/kubernetes/**/manifests/**"
       - "**/tests/test_manifest**"
       - "!**.md"