Remove git checkout.

Author: htorianik

.github/workflows/codeql-analysis.yml

@@ -23,11 +23,6 @@ jobs:
         # a pull request then we can checkout the head.
           fetch-depth: 2
 
-    # If this run was triggered by a pull request event, then checkout
-    # the head of the pull request instead of the merge commit.
-      - run: git checkout HEAD^2
-        if: ${{ github.event_name == 'pull_request' }}
-
     # Initializes the CodeQL tools for scanning.
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v2