Update ci.yml

Author: bdukes

.github/workflows/ci.yml

@@ -29,6 +29,12 @@ jobs:
     - name: Setup MSBuild.exe
       uses: microsoft/setup-msbuild@v1.0.3
 
+    - name: Install .NET Core
+      uses: actions/setup-dotnet@v1.8.1
+      with:
+        dotnet-version: '6.0'
+        include-prerelease: True
+    
     - name: Setup NuGet.exe for use with actions
       uses: NuGet/setup-nuget@v1.0.5
       with: