Add a changelog entry and @mathstuf to the contributors list

Author: tomhoule

CHANGELOG.md

@@ -38,6 +38,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 - The CLI now supports the `--authorization` flag to pass the contents of an `Authorization` header. Thanks to @h-michael for the [PR](https://github.com/tomhoule/graphql-client/pull/92)!
 
+- Improved some codegen error messages, giving more context. Thank @mathstuf!
+
 ### Fixed
 
 - Handle all Rust keywords as field names in codegen by appending `_` to the generated names, so a field called `type` in a GraphQL query will become a `type_` field in the generated struct. Thanks to @scrogson!

README.md

@@ -146,6 +146,7 @@ There is an embryonic CLI for downloading schemas - the plan is to make it somet
 Warmest thanks to all those who contributed in any way (not only code) to this project:
 
 - Alex Vlasov (@indifferentalex)
+- Ben Boeckel (@mathstuf)
 - Christian Legnitto (@LegNeato)
 - Dirkjan Ochtman (@djc)
 - Fausto Nunez Alberro (@brainlessdeveloper)