Clone boilerplate using a tag
The code should clone the boilerplate using a tag otherwise updates on the structure of the boilerplate may cause a bunch of issues here.

Block of code to change: https://github.com/graphql-community/create-graphql/blob/master/packages/generator/src/app/index.js#L38-L42

Depends on https://github.com/entria/graphql-dataloader-boilerplate/issues/62.

cc @graphql-community/contributors.