Merge pull request #2158 from alasdairhurst/master

#2157: Update schema to validate refs in headers of encoding objects

Author: MikeRalphson

schemas/v3.0/schema.yaml

@@ -1,4 +1,4 @@
-id: https://spec.openapis.org/oas/3.0/schema/2019-04-02
+id: https://spec.openapis.org/oas/3.0/schema/2020-02-25
 $schema: http://json-schema.org/draft-04/schema#
 description: Validation schema for OpenAPI Specification 3.0.X.
 type: object
@@ -987,7 +987,9 @@ definitions:
       headers:
         type: object
         additionalProperties:
-          $ref: '#/definitions/Header'
+          oneOf:
+            - $ref: '#/definitions/Header'
+            - $ref: '#/definitions/Reference'
       style:
         type: string
         enum: