Improve CodeQL workflow

Author: andyone

.github/workflows/codeql.yml

@@ -6,7 +6,12 @@ on:
   pull_request:
     branches: [master]
   schedule:
-    - cron: '0 17 * * 1,3,5'
+    - cron: '0 3 * * */2'
+
+permissions:
+  security-events: write
+  actions: read
+  contents: read
 
 jobs:
   analyse:
@@ -15,13 +20,10 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
       with:
         fetch-depth: 2
 
-    - run: git checkout HEAD^2
-      if: ${{ github.event_name == 'pull_request' }}
-
     - name: Initialize CodeQL
       uses: github/codeql-action/init@v1
       with: