Bump FluentAssertions in /src/Objectivity.AutoFixture.XUnit2.Core.Tests

Bumps [FluentAssertions](https://github.com/fluentassertions/fluentassertions) from 6.12.0 to 6.12.1.
- [Release notes](https://github.com/fluentassertions/fluentassertions/releases)
- [Changelog](https://github.com/fluentassertions/fluentassertions/blob/develop/AcceptApiChanges.ps1)
- [Commits](fluentassertions/fluentassertions@6.12.0...6.12.1)

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

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

src/Objectivity.AutoFixture.XUnit2.Core.Tests/Objectivity.AutoFixture.XUnit2.Core.Tests.csproj

@@ -57,7 +57,7 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="FluentAssertions" Version="6.12.0" />
+    <PackageReference Include="FluentAssertions" Version="6.12.1" />
     <PackageReference Include="JetBrains.Annotations" Version="2024.2.0" />
     <PackageReference Include="Microsoft.CodeAnalysis.NetAnalyzers" Version="8.0.0">
       <PrivateAssets>all</PrivateAssets>