Merge pull request #1435 from dotnet/dependabot/nuget/AsyncRx.NET/System.Reactive-5.0.0

Bump System.Reactive from 4.0.0-preview00001 to 5.0.0 in /AsyncRx.NET

AsyncRx.NET/ApiCompare/ApiCompare.csproj

@@ -6,7 +6,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="System.Reactive" Version="4.0.0-preview00001" />
+    <PackageReference Include="System.Reactive" Version="5.0.0" />
   </ItemGroup>
 
   <ItemGroup>