MAINT/TST: Add requirement to run linting on push/PR

We want this to be noticed as early as possible

Author: Kai-Striega

.github/workflows/lint.yml

@@ -4,6 +4,8 @@ on:
   pull_request:
     branches:
       - main
+      - push
+      - pull_request
 
 permissions:
    contents: read  # to fetch code (actions/checkout)