Fix registration problems where people's names are called invalid (#2377)

It is now used as a display name.

Author: lawik

lib/nerves_hub/accounts/user.ex

@@ -105,7 +105,6 @@ defmodule NervesHub.Accounts.User do
     |> update_change(:name, &trim/1)
     |> validate_required([:name])
     |> validate_length(:name, min: 2, max: 100)
-    |> validate_format(:name, ~r/^[a-zA-Z\'\- ]+$/, message: "has invalid character(s)")
   end
 
   defp validate_email(changeset, _opts) do