v6.0.0

Breaking changes

• This package is now updated for Apollo Server v4, which also makes it easier to use without apollo server.
  This changes how initialisation works, there is no longer a need to call .initialize() on the class after creating it with new
  Instead you just pass it all to the constructor, therefore the second options argument of the constructor now takes a cache as well, and if none is provided an in-memory key value cache will be used
• documents now automatically get createdAt and updatedAt timestamps