build(deps): Bump Microsoft.Reactive.Testing from 5.0.0 to 6.0.0 (#735)

Bumps [Microsoft.Reactive.Testing](https://github.com/dotnet/reactive) from 5.0.0 to 6.0.0.
- [Release notes](https://github.com/dotnet/reactive/releases)
- [Commits](https://github.com/dotnet/reactive/commits)

---
updated-dependencies:
- dependency-name: Microsoft.Reactive.Testing
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

Xamarin/Cinephile/Cinephile.UnitTests/Cinephile.UnitTests.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <TargetFramework>net6.0</TargetFramework>
@@ -16,7 +16,7 @@
     <PackageReference Include="NUnit3TestAdapter" Version="4.4.2" />
     <PackageReference Include="Moq" Version="4.18.4" />
     <PackageReference Include="Microsoft.CodeCoverage" Version="17.5.0" />
-    <PackageReference Include="Microsoft.Reactive.Testing" Version="5.0.0" />
+    <PackageReference Include="Microsoft.Reactive.Testing" Version="6.0.0" />
   </ItemGroup>
   <ItemGroup>
     <Folder Include="ViewModels\" />