ci: run codeql on pull requests #24545

Also use cache to save 1 minute.

.github/workflows/codeql.yml

@@ -1,6 +1,11 @@
 name: "CodeQL"
 
 on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    # The branches below must be a subset of the branches above
+    branches: [ "master" ]
   schedule:
     - cron: '42 0 * * 0'
   workflow_dispatch:
@@ -25,6 +30,8 @@ jobs:
       with:
         languages: cpp
 
+    - uses: ./.github/actions/cache
+
     - run: make
 
     - name: Perform CodeQL Analysis