Update codeql.yml

https://docs.github.com/en/code-security/code-scanning/creating-an-advanced-setup-for-code-scanning/customizing-your-advanced-setup-for-code-scanning#avoiding-unnecessary-scans-of-pull-requests

.github/workflows/codeql.yml

@@ -16,6 +16,9 @@ on:
     branches: [ "main" ]
   pull_request:
     branches: [ "main" ]
+    paths-ignore:
+      - '**/*.md'
+      - '**/*.txt'
   schedule:
     - cron: '33 9 * * 6'