feature: Don't pull Terminal.Gui from NuGet, use ReactiveMarbles.ObservableEvents (#1440)

* Don't pull Terminal.Gui from NuGet, use ReactiveMarbles source generator

* Target net5.0

ReactiveExample/LoginView.cs

@@ -3,6 +3,7 @@ using System.Reactive.Linq;
 using NStack;
 using ReactiveUI;
 using Terminal.Gui;
+using ReactiveMarbles.ObservableEvents;
 
 namespace ReactiveExample {
 	public class LoginView : Window, IViewFor<LoginViewModel> {

ReactiveExample/ReactiveExample.csproj

@@ -1,13 +1,17 @@
 <Project Sdk="Microsoft.NET.Sdk">
     <PropertyGroup>
         <OutputType>Exe</OutputType>
-        <TargetFramework>netcoreapp3.1</TargetFramework>
+        <TargetFramework>net5.0</TargetFramework>
     </PropertyGroup>
     <ItemGroup>
-        <PackageReference Include="Pharmacist.MsBuild" Version="2.0.8" PrivateAssets="all" />
-        <PackageReference Include="Pharmacist.Common" Version="2.0.8" />
-        <PackageReference Include="Terminal.Gui" Version="1.1.1.*" />
         <PackageReference Include="ReactiveUI.Fody" Version="14.2.1" />
         <PackageReference Include="ReactiveUI" Version="14.2.1" />
+        <PackageReference
+            Include="ReactiveMarbles.ObservableEvents.SourceGenerator"
+            Version="1.1.3"
+            PrivateAssets="all" />
+    </ItemGroup>
+    <ItemGroup>
+        <ProjectReference Include="..\Terminal.Gui\Terminal.Gui.csproj" />
     </ItemGroup>
 </Project>