deps: Bump FluentAssertions from 8.5.0 to 8.6.0 (#4)

---
updated-dependencies:
- dependency-name: FluentAssertions
  dependency-version: 8.6.0
  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]

QsNet.Tests/QsNet.Tests.csproj

@@ -5,7 +5,7 @@
         <IsPackable>false</IsPackable>
     </PropertyGroup>
     <ItemGroup>
-        <PackageReference Include="FluentAssertions" Version="8.5.0"/>
+        <PackageReference Include="FluentAssertions" Version="8.6.0"/>
         <PackageReference Include="JetBrains.Annotations" Version="2025.2.0"/>
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.14.1"/>
         <PackageReference