chore(deps): update dependency fluentassertions to v6.12.0

Author: renovate[bot]

Diff for: Directory.Packages.props

@@ -17,7 +17,7 @@
     <PackageVersion Include="BenchmarkDotNet" Version="0.13.1" />
     <PackageVersion Include="coverlet.collector" Version="3.1.2" />
     <PackageVersion Include="coverlet.msbuild" Version="3.1.2" />
-    <PackageVersion Include="FluentAssertions" Version="6.7.0" />
+    <PackageVersion Include="FluentAssertions" Version="6.12.0" />
     <PackageVersion Include="GitHubActionsTestLogger" Version="2.3.3" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.2.0" />
     <PackageVersion Include="NSubstitute" Version="5.0.0" />