build(deps): Bump ReactiveUI.Testing from 16.2.6 to 18.0.10 (#79)

Bumps [ReactiveUI.Testing](https://github.com/reactiveui/reactiveui) from 16.2.6 to 18.0.10.
- [Release notes](https://github.com/reactiveui/reactiveui/releases)
- [Commits](reactiveui/ReactiveUI@16.2.6...18.0.10)

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

Signed-off-by: dependabot[bot] <support@github.com>

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

Author: dependabot[bot]

src/ReactiveMarbles.CacheDatabase.Tests/ReactiveMarbles.CacheDatabase.Tests.csproj

@@ -19,7 +19,7 @@
     </PackageReference>
     <PackageReference Include="FluentAssertions" Version="6.6.0" />
     <PackageReference Include="Microsoft.Reactive.Testing" Version="5.0.0" />
-    <PackageReference Include="ReactiveUI.Testing" Version="16.2.6" />
+    <PackageReference Include="ReactiveUI.Testing" Version="18.0.10" />
   </ItemGroup>
 
   <ItemGroup>