Add PATCH HTTP method

Author: PhilT

lib/jsonapi_spec_helpers/helpers.rb

@@ -92,6 +92,10 @@ def jsonapi_put(url, payload)
       put url, params: payload.to_json, headers: jsonapi_headers
     end
 
+    def jsonapi_patch(url, payload)
+      patch url, params: payload.to_json, headers: jsonapi_headers
+    end
+
     def jsonapi_delete(url)
       delete url, headers: jsonapi_headers
     end