Update preview_metadata.yml

Author: C-Achard

.github/workflows/preview_metadata.yml

@@ -4,7 +4,7 @@ name: napari hub Preview Page # we use this name to find your preview page artif
 on:
   pull_request:
     branches:
-      - '**'
+      - 'test'
 
 jobs:
   preview-page: