200 PUT response schema fix

Author: Milan Zolota

specification/apimanagement/resource-manager/Microsoft.ApiManagement/preview/2021-04-01-preview/apimpolicyfragments.json

@@ -234,7 +234,7 @@
           "200": {
             "description": "Policy fragment configuration of the Api Management service was successfully updated.",
             "schema": {
-              "$ref": "./definitions.json#/definitions/PolicyContract"
+              "$ref": "./definitions.json#/definitions/PolicyFragmentContract"
             },
             "headers": {
               "ETag": {