`graphql_relay` dependency error

[fabianriewe]

Using graphql-relay==3.1.4 and graphene-mongo==0.2.14 creates an error due to a rename of graphql_relay.connection.arrayconnection to graphql_relay.connection.array_connection. There are two imports which need to be updated.

[RoyalGoose]

i have same error, did you fix it?

[blochs]

#191