Bump FluentAssertions from 6.7.0 to 6.8.0

Bumps [FluentAssertions](https://github.com/fluentassertions/fluentassertions) from 6.7.0 to 6.8.0.
- [Release notes](https://github.com/fluentassertions/fluentassertions/releases)
- [Changelog](https://github.com/fluentassertions/fluentassertions/blob/develop/AcceptApiChanges.ps1)
- [Commits](fluentassertions/fluentassertions@6.7.0...6.8.0)

---
updated-dependencies:
- dependency-name: FluentAssertions
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

tests/Directory.Build.props

@@ -3,7 +3,7 @@
 
   <ItemGroup Condition="$(MSBuildProjectName) != 'LinkDotNet.Blog.TestUtilities'">
     <PackageReference Include="bunit" Version="1.11.7" />
-    <PackageReference Include="FluentAssertions" Version="6.7.0" />
+    <PackageReference Include="FluentAssertions" Version="6.8.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.5.0-preview-20221003-04" />
     <PackageReference Include="Moq" Version="4.18.2" />
     <PackageReference Include="xunit" Version="2.4.2" />