[Github] Add path filtering to CodeQL workflow

This workflow should only be triggering on PRs that touch Github
workflows. This is not the case currently because I forgot to add path
filtering in the original implementation.

Author: boomanaiden154

.github/workflows/gha-codeql.yml

@@ -7,6 +7,8 @@ on:
   pull_request:
     branches:
       - main
+    paths:
+      - '.github/**'
   schedule:
     - cron: '30 0 * * *'