Bump FluentAssertions from 5.10.3 to 6.4.0 (#238)

Bumps [FluentAssertions](https://github.com/fluentassertions/fluentassertions) from 5.10.3 to 6.4.0.
- [Release notes](https://github.com/fluentassertions/fluentassertions/releases)
- [Changelog](https://github.com/fluentassertions/fluentassertions/blob/master/AcceptApiChanges.ps1)
- [Commits](fluentassertions/fluentassertions@5.10.3...6.4.0)

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

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

src/common.props

@@ -17,7 +17,7 @@ Upgraded to [Petabridge.Cmd v0.8.5](https://cmd.petabridge.com/articles/RELEASE_
   <PropertyGroup>
     <XunitVersion>2.4.1</XunitVersion>
     <MicrosoftSdkVersion>17.0.0</MicrosoftSdkVersion>
-    <FluentAssertionsVersion>5.10.3</FluentAssertionsVersion>
+    <FluentAssertionsVersion>6.4.0</FluentAssertionsVersion>
     <NetCoreVersion>netcoreapp3.1</NetCoreVersion>
     <NetStandardVersion>netstandard1.6</NetStandardVersion>
     <NetFrameworkLibVersion>net461</NetFrameworkLibVersion>