Upgrade herrera-io/json dependency to 2.* version

[tyranron]

This PR upgrades herrera-io/json dependency version to 2.* branch.

Why?

With current sticking to 1.* version this project creates problems in dependencies resolving.

For example (composer.json):

{
  "require-dev": {
    "composer/composer": "~1.6",
    "phpdocumentor/phpdocumentor": "~2.9"
  }
}

These are the latest versions of Composer and phpDocumentor at the moment. But Composer won't resolve this, because phpdocumentor/phpdocumentor requires this project, and this project requires herrera-io/json to be 1.*, and that one requires justinrainbow/json-schema to be >=1.0,<2.0-dev. Which is incompatible with requirement of composer/composer (justinrainbow/json-schema to be ^3.0 || ^4.0 || ^5.0).

The only possible way to resolve this at the moment is to downgrade composer/composer to ~1.3 which considers 1.* versions of justinrainbow/json-schema.

Solution

Upgrading herrera-io/json to 2.* branch will require a ^4.1 of justinrainbow/json-schema, which will cause much less problems in transitive dependencies.

[tyranron]

@kherge ping