[skip ci] Limit push runs to default branch

Author: jwodder

.github/workflows/test.yml

@@ -3,8 +3,8 @@ name: Test
 on:
   pull_request:
   push:
-    branches-ignore:
-      - 'dependabot/**'
+    branches:
+      - master
   schedule:
     - cron: '0 6 * * *'