CI: disable CodeQL for doc-only PRs

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

Author: AkihiroSuda

.github/workflows/codeql.yaml

@@ -1,10 +1,19 @@
 name: "CodeQL Advanced"
 
 on:
+  # paths-ignore should be kept in sync with test.yml
   push:
     branches: ["master"]
+    paths-ignore:
+    - "docs/**"
+    - "website/**"
+    - "**.md"
   pull_request:
     branches: ["master"]
+    paths-ignore:
+    - "docs/**"
+    - "website/**"
+    - "**.md"
   schedule:
   - cron: '33 19 * * 5'
   workflow_dispatch: