This commit implements a new proc macro `impl_object` that replaces
the old graphql_object! macro.
The code shares a lot of similarities with the GraphQLObject
custom derive, so the code was unified to handle both
more generically.
Also, doc comment processing was standardized and improved.
* Bump` juniper`, `juniper_codegen`, and `juniper_tests` versions.
* Bump integration crate requirements to include 0.10.0. `juniper_iron` gets a semver breaking version as it has a breaking change but `juniper_iron` does not.
* Move `juniper_rocket` changelog into one file. This aligns with `juniper_iron` and will be easier
to automate in the future.
* Let `juniper_warp` and `juniper_hyper` use `0.9.x` versions of Juniper. They don't rely on anything in 0.10.0 so don't require it.
