Bump FluentAssertions from 6.11.0 to 6.12.0 (#55)

Bumps [FluentAssertions](https://github.com/fluentassertions/fluentassertions) from 6.11.0 to 6.12.0.
- [Release notes](https://github.com/fluentassertions/fluentassertions/releases)
- [Changelog](https://github.com/fluentassertions/fluentassertions/blob/develop/AcceptApiChanges.ps1)
- [Commits](fluentassertions/fluentassertions@6.11.0...6.12.0)

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

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

Author: dependabot[bot]

src/Directory.Build.props

@@ -22,7 +22,7 @@
 
     <AkkaVersion>1.5.12</AkkaVersion>
     <AkkaHostingVersion>1.5.12.1</AkkaHostingVersion>
-    <FluentAssertionsVersion>6.11.0</FluentAssertionsVersion>
+    <FluentAssertionsVersion>6.12.0</FluentAssertionsVersion>
     <BenchmarkDotNetVersion>0.13.8</BenchmarkDotNetVersion>
   </PropertyGroup>