[workflows] Test builds with Release configuration.

Author: mpaperno

.github/workflows/dotnet.yml

@@ -34,7 +34,7 @@ jobs:
         run: dotnet restore
 
       - name: Build
-        run: dotnet build --no-restore
+        run: dotnet build --no-restore --configuration Release
 
 #    - name: Test
 #      run: dotnet test --no-build --verbosity normal