Update dependency FluentAssertions to v6.9.0

Author: renovate[bot]

Directory.Packages.props

@@ -36,7 +36,7 @@
     <PackageVersion Include="coverlet.msbuild" Version="3.2.0" />
     <PackageVersion Include="FakeItEasy" Version="7.3.1" />
     <PackageVersion Include="FakeItEasy.Analyzer.CSharp" Version="6.1.0" />
-    <PackageVersion Include="FluentAssertions" Version="6.8.0" />
+    <PackageVersion Include="FluentAssertions" Version="6.9.0" />
     <PackageVersion Include="FluentAssertions.Analyzers" Version="0.17.2" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.4.1" />
     <PackageVersion Include="Rocket.Surgery.Extensions.Testing.FakeItEasy" Version="7.1.4" />