Fix tests workflow trigger to match branch names containing '/'

A single '*' in a GitHub Actions branch glob does not match '/', so
pushes to branches like feat/modernization never triggered the tests
workflow; use '**' instead.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: vthorsteinsson

.github/workflows/python-package.yml

@@ -2,9 +2,10 @@ name: tests
 
 on:
   push:
-    branches: [ "*" ]
+    # Note: "**" is required to match branch names containing '/'
+    branches: [ "**" ]
   pull_request:
-    branches: [ "*" ]
+    branches: [ "**" ]
 
 jobs:
   build: