Update dependency FluentAssertions to v8

Author: renovate[bot]

tests/TBC.OpenAPI.SDK.OnlineInstallments.Tests/TBC.OpenAPI.SDK.OnlineInstallments.Tests.csproj

@@ -8,7 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="FluentAssertions" Version="6.7.0" />
+    <PackageReference Include="FluentAssertions" Version="8.5.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.11.0" />
     <PackageReference Include="Moq" Version="4.18.1" />
     <PackageReference Include="WireMock.Net" Version="1.5.0" />