CodeQL updates.

.github/workflows/codeql-analysis.yml

@@ -0,0 +1,37 @@
+'name: "CodeQL"
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  analyse:
+    name: Analyse
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+        with:
+          # We must fetch at least the immediate parents so that if this is
+          # 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
+
+      # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java)
+      - name: Autobuild
+        uses: github/codeql-action/autobuild@v2
+
+      - name: Perform CodeQL Analysis
+        uses: github/codeql-action/analyze@v2