OpenAPI-to-GraphQL v2.0.0

• Support for allOf, oneOf, anyOf, and not JSON schema keywords
  • Including proper fallback for edge cases
• Enum values are in ALL_CAPS, following GraphQL convention
• Support for x-www-form-urlencoded request bodies
• Add genericPayloadArgName option
• Add simpleNames option
  • Create field and type names with minimal changes/formatting
• Add singularNames option
  • Create semantically meaningful names from analyzing the operation path (experimental)
• Fix bug where linked fields were not using requestOptions
• Numerous code improvements

Special thanks @cliffpyles, @YoonsLee, @sotaokuhama, @ibudden