Run the static code checks on push and when manually triggered

GHA that only runs on pull_request is hard to test; I have to create PR to see it run.
With this change, the action can be tested in my personal fork before I create a PR

.github/workflows/code-quality.yaml

@@ -1,6 +1,9 @@
 ---
 name: Code static analysis
-on: [pull_request]  # yamllint disable-line rule:truthy
+on:  # yamllint disable-line rule:truthy
+  push:
+  pull_request:
+  workflow_dispatch:
 
 permissions:
   contents: read