Build single version for docs pipeline

Author: TheBoxyBear

.github/workflows/docfx.yml

@@ -31,7 +31,7 @@ jobs:
       with:
         dotnet-version: 10.0
 
-    - run: dotnet build ChartTools/ChartTools/ChartTools.csproj -p ProduceOnlyReferenceAssembly=true
+    - run: dotnet build ChartTools/ChartTools/ChartTools.csproj --framework net10.0 -p ProduceOnlyReferenceAssembly=true
     - run: dotnet tool update -g docfx
     - run: docfx ChartTools/Docs/docfx.json