FluentAssertions replace with Shouldly

Just press cmd+H in Visual Studio and replace
[crayon-680818c822261433225475/]
and
[crayon-680818c822268436189001/]
99% percent of the errors should be gone.

If you like to stay with FluentAssertions (which I do not recommend), open your .csproj file and put brackets around the version. This will prevent you upgrading to version 8
[crayon-680818c822269418429019/]