build(deps): bump Microsoft.Reactive.Testing from 5.0.0 to 6.0.0 in /integrationtests (#3550)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

src/Directory.build.props

@@ -49,7 +49,7 @@
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5" />
     <PackageReference Include="Xunit.StaFact" Version="1.1.11" />
     <PackageReference Include="FluentAssertions" Version="6.11.0" />
-    <PackageReference Include="Microsoft.Reactive.Testing" Version="5.0.0" />
+    <PackageReference Include="Microsoft.Reactive.Testing" Version="6.0.0" />
     <PackageReference Include="PublicApiGenerator" Version="11.0.0" />
     <PackageReference Include="coverlet.msbuild" Version="6.0.0" PrivateAssets="All" />
     <PackageReference Include="Verify.Xunit" Version="20.3.0" />

src/ReactiveUI.Testing/ReactiveUI.Testing.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="MSBuild.Sdk.Extras">
+<Project Sdk="MSBuild.Sdk.Extras">
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;net6.0;net7.0;Xamarin.iOS10;Xamarin.Mac20;Xamarin.TVOS10;MonoAndroid12.0;MonoAndroid12.1;MonoAndroid13.0</TargetFrameworks>
     <TargetFrameworks Condition=" '$(OS)' == 'Windows_NT' ">$(TargetFrameworks);net472</TargetFrameworks>
@@ -18,7 +18,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.Reactive.Testing" Version="5.0.0" />
+    <PackageReference Include="Microsoft.Reactive.Testing" Version="6.0.0" />
     <ProjectReference Include="..\ReactiveUI\ReactiveUI.csproj" />
   </ItemGroup>