Explicit .NET 9 install

Author: NickCraver

.github/workflows/codeql.yml

@@ -29,10 +29,15 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         fetch-depth: 0
 
+    - name: Setup .NET
+      uses: actions/setup-dotnet@v4
+      with:
+        dotnet-version: '9.0.x'
+
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
       uses: github/codeql-action/init@v3