Update JSON example files

Author: ralfhandl

examples/v3.0/callback-example.json

@@ -27,6 +27,7 @@
             "content": {
               "application/json": {
                 "schema": {
+                  "type": "object",
                   "description": "subscription information",
                   "required": ["subscriptionId"],
                   "properties": {

examples/v3.0/uspto.json

@@ -223,12 +223,12 @@
                 },
                 "apiUrl": {
                   "type": "string",
-                  "format": "uriref",
+                  "format": "uri-reference",
                   "description": "The URL describing the dataset's fields"
                 },
                 "apiDocumentationUrl": {
                   "type": "string",
-                  "format": "uriref",
+                  "format": "uri-reference",
                   "description": "A URL to the API console for each API"
                 }
               }

examples/v3.1/webhook-example.json

@@ -28,6 +28,7 @@
   "components": {
     "schemas": {
       "Pet": {
+        "type": "object",
         "required": ["id", "name"],
         "properties": {
           "id": {