Try to fix codeql autobuild

Author: Warren Buckley

.github/workflows/codeql-analysis.yml

@@ -43,6 +43,12 @@ jobs:
       with:
         fetch-depth: 0
 
+    - name: Setup .NET
+      uses: actions/setup-dotnet@v1
+      with:
+        dotnet-version: '6.0.x'
+        include-prerelease: true
+
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
       uses: github/codeql-action/init@v1