Update dependencies from https://github.com/dotnet/efcore build 20200220.8 (#19222)

- Microsoft.EntityFrameworkCore.Tools - 5.0.0-preview.2.20120.8
- Microsoft.EntityFrameworkCore.SqlServer - 5.0.0-preview.2.20120.8
- dotnet-ef - 5.0.0-preview.2.20120.8
- Microsoft.EntityFrameworkCore - 5.0.0-preview.2.20120.8
- Microsoft.EntityFrameworkCore.InMemory - 5.0.0-preview.2.20120.8
- Microsoft.EntityFrameworkCore.Relational - 5.0.0-preview.2.20120.8
- Microsoft.EntityFrameworkCore.Sqlite - 5.0.0-preview.2.20120.8