Fix build path.

.github/workflows/dotnet-core.yml

@@ -91,7 +91,7 @@ jobs:
         dotnet-quality: 'ga'
 
     - name: Build Release Terminal.Gui
-      run: dotnet build ../Terminal.Gui/Terminal.Gui.csproj --configuration Release
+      run: dotnet build Terminal.Gui/Terminal.Gui.csproj --configuration Release
 
     - name: Pack Release Terminal.Gui
       run: dotnet pack Terminal.Gui/Terminal.Gui.csproj --configuration Release --output ./local_packages