Bump FluentAssertions from 6.8.0 to 6.9.0 (#1172)

Bumps [FluentAssertions](https://github.com/fluentassertions/fluentassertions) from 6.8.0 to 6.9.0.
- [Release notes](https://github.com/fluentassertions/fluentassertions/releases)
- [Changelog](https://github.com/fluentassertions/fluentassertions/blob/develop/AcceptApiChanges.ps1)
- [Commits](https://github.com/fluentassertions/fluentassertions/compare/6.8.0...6.9.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

tests/KubernetesClient.Tests/KubernetesClient.Tests.csproj

@@ -7,7 +7,7 @@
 
   <ItemGroup>
       <PackageReference Include="MartinCostello.Logging.XUnit" Version="0.3.0" />
-      <PackageReference Include="FluentAssertions" Version="6.8.0" />
+      <PackageReference Include="FluentAssertions" Version="6.9.0" />
       <PackageReference Include="Microsoft.Extensions.Logging" Version="7.0.0" />
       <PackageReference Include="System.IO.Abstractions.TestingHelpers" Version="19.1.5" />
       <PackageReference Include="System.Reactive" Version="5.0.0" />