added code coverage arguments for test cmd

Author: Petr Sramek

.github/workflows/dotnet.yml

@@ -48,4 +48,4 @@ jobs:
         path: .
         merge-multiple: true
     - name: Test
-      run: dotnet test --no-restore --no-build --configuration Release --verbosity normal
+      run: dotnet test --no-restore --no-build --configuration Release --verbosity normal --collect:"XPlat Code Coverage" --logger trx --results-directory code-coverage