ci: bump actions/checkout from 2.4.0 to 3 (#715)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/codeql.yml

@@ -10,7 +10,7 @@ jobs:
   CodeQL-Build:
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v2.4.0
+      - uses: actions/checkout@v3
 
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v1