Changelog
* Fix a typo in a deprecation warning 9202021fc87db9c175e115016cd53e5d9d085ac6
* Fix collections import for Python >3.3 cdb299df3efda82a09cbb282e561c6c8aaa2efdf
* Add dict support for the default resolver 1760eaf995e2623aee4afca48ad5be0cd9098fbe
* Fix UnicodeDecodeError in format_error 87b615605ac9724c4f945e220e67b5b2d0461424
* Add extensions support to GraphQLError 3ba7f9218bca7a039b109b103cf57b1511d970c7
* Add traceback to errors from failed promises 8f736b7a6b052c07347dbd57e00bc8221af71faa
* Lots of internal clean up
Full changelog: https://github.com/graphql-python/graphql-core/compare/v2.1.0...v2.2.0