ci(helm): sync README to root of helm repository on release (#8263)

Include helm/rustfs/README.md in the uploaded helm-package artifact so
publish-helm-package updates the root README.md in rustfs/helm.

The build-helm-package job copies helm/README.md into helm/rustfs/
before running helm package, but upload-artifact previously uploaded
only helm/rustfs/*.tgz. Because both files share the helm/rustfs/
parent directory, actions/upload-artifact places both the chart
archive and README.md at the artifact root, and download-artifact
extracts README.md into the root of rustfs/helm alongside the tarball.

.github/workflows/helm-package.yml

@@ -145,7 +145,9 @@ jobs:
         uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
         with:
           name: helm-package
-          path: helm/rustfs/*.tgz
+          path: |
+            helm/rustfs/*.tgz
+            helm/rustfs/README.md
           retention-days: 1
 
   publish-helm-package:

scripts/test_helm_release_workflow.py

@@ -113,6 +113,23 @@ sleep() {
         self.assertLess(gate, package)
         self.assertNotIn("continue-on-error", workflow[gate:package])
 
+    def test_upload_artifact_includes_chart_and_readme(self):
+        workflow = WORKFLOW.read_text()
+        copy_readme = workflow.index("cp helm/README.md helm/rustfs/")
+        upload = workflow.index("      - name: Upload helm package as artifact")
+        self.assertLess(copy_readme, upload)
+
+        publish = workflow.index("  publish-helm-package:", upload)
+        upload_step = workflow[upload:publish]
+        expected_path = "path: |\n            helm/rustfs/*.tgz\n            helm/rustfs/README.md\n"
+        self.assertIn(expected_path, upload_step)
+
+        download = workflow.index("      - name: Download helm package", publish)
+        push_step = workflow.index("      - name: Push helm package and index file", download)
+        download_step = workflow[download:push_step]
+        self.assertIn("name: helm-package", download_step)
+        self.assertIn("path: ./", download_step)
+
 
 if __name__ == "__main__":
     unittest.main()