fix: lock FluentAssertions version to 7.x to prevent unintended upgrade (#39)

Author: DevD4v3

Directory.Packages.props

@@ -14,7 +14,7 @@
     <PackageVersion Include="DotEnv.Core" Version="3.0.0" />
     <PackageVersion Include="Microsoft.AspNetCore.Mvc.Testing" Version="7.0.3" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.1.0" />
-    <PackageVersion Include="FluentAssertions" Version="6.10.0" />
+    <PackageVersion Include="FluentAssertions" Version="[7.0.0,8.0.0)" />
     <PackageVersion Include="NUnit" Version="3.13.3" />
     <PackageVersion Include="NUnit3TestAdapter" Version="4.3.0" />
     <PackageVersion Include="NUnit.Analyzers" Version="3.5.0" />