chore(deps): update dependency microsoft.reactive.testing to 6.1.0 (#307)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

src/Directory.Packages.props

@@ -37,7 +37,7 @@
     <PackageVersion Include="xunit.runner.visualstudio" Version="3.1.5" />
     <PackageVersion Include="Xunit.StaFact" Version="3.0.13" />
     <PackageVersion Include="FluentAssertions" Version="8.7.1" />
-    <PackageVersion Include="Microsoft.Reactive.Testing" Version="6.0.2" />
+    <PackageVersion Include="Microsoft.Reactive.Testing" Version="6.1.0" />
     <PackageVersion Include="PublicApiGenerator" Version="11.4.6" />
     <PackageVersion Include="coverlet.msbuild" Version="6.0.4" />
     <PackageVersion Include="Verify.Xunit" Version="30.19.2" />