Update dotnet.yml

Author: mckaragoz

.github/workflows/dotnet.yml

@@ -23,3 +23,5 @@ jobs:
       run: dotnet build --no-restore
     - name: Test
       run: dotnet test --no-build --verbosity normal
+    - name: Codecov
+      uses: codecov/codecov-action@v3.1.1