This PR adds support for "vendor extensions" option on a field level.
This allows to specify some additional metadata that can be passed to generated json-schemas. Especially, this is a powerful feature in case generated json-schemas referenced in OpenAPI specification which is used to generate client / server with openapi-generator.
In this case we can easily add support, for example, of validation rules by adding such vendor extension to any field: https://github.com/OpenAPITools/openapi-generator/issues/1145
This PR adds support for "vendor extensions" option on a field level. This allows to specify some additional metadata that can be passed to generated json-schemas. Especially, this is a powerful feature in case generated json-schemas referenced in OpenAPI specification which is used to generate client / server with openapi-generator. In this case we can easily add support, for example, of validation rules by adding such vendor extension to any field: https://github.com/OpenAPITools/openapi-generator/issues/1145
@chrusty please review