update API contract to match actual wire format for metadata and attributes

opengin/contracts/rest/ingestion_api.yaml

@@ -107,14 +107,29 @@ components:
         name:
           $ref: '#/components/schemas/TimeBasedValue'
         metadata:
-          type: object
-          additionalProperties: true
+          type: array
+          items:
+            type: object
+            properties:
+              key:
+                type: string
+              value:
+                type: object
+                additionalProperties: true
         attributes:
-          type: object
-          additionalProperties:
-            type: array
-            items:
-              $ref: '#/components/schemas/TimeBasedValue'
+          type: array
+          items:
+            type: object
+            properties:
+              key:
+                type: string
+              value:
+                type: object
+                properties:
+                  values:
+                    type: array
+                    items:
+                      $ref: '#/components/schemas/TimeBasedValue'
         relationships:
           type: array
           items: