chore(deps): update dependency fluentassertions to 6.12.1

Author: renovate[bot]

Diff for: src/Directory.build.props

@@ -54,7 +54,7 @@
     <PackageReference Include="xunit.runner.console" Version="2.9.0" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2" />
     <PackageReference Include="Xunit.StaFact" Version="1.1.11" />
-    <PackageReference Include="FluentAssertions" Version="6.12.0" />
+    <PackageReference Include="FluentAssertions" Version="6.12.1" />
     <PackageReference Include="Microsoft.Reactive.Testing" Version="6.0.1" />
     <PackageReference Include="PublicApiGenerator" Version="11.1.0" />
     <PackageReference Include="coverlet.msbuild" Version="6.0.2" PrivateAssets="All" />