Public release of GraphQL-core-next, based on GraphQL.js v14.3.0.
In addition to incorporating the latest changes from GraphQL.js
(see the list of changes in GraphQL.js [v14.3.0](https://github.com/graphql/graphql-js/releases/tag/v14.3.0)),
which include the addition of a new utility function `strip_ignored_characters`,
this release also contains the following improvements and changes:
* `specified_directives` and similar lists are now read only lists (31)
* `introspection_types` is now a read only dict
* Minor fixes in the Sphinx docs and some docstrings