After Core 3.0 upgrade, impossible to add-migration with EF Core 3.0

I had a reference of Microsoft.EntityFrameworkCore version 2.2.6 in a linked project which had the database connection string. I upgraded and it's works

I had the same issue after upgrading to version 3.0. After reading this, I installed the Microsoft.EntityFrameworkCore.Design nuget package and the problem was resolved.