fix: missing type on some objects

this is not required but some tools will throw warnings and its probably a good idea to be specific.

openapi.yaml

@@ -104,6 +104,7 @@ paths:
           content:
             application/json:
               schema:
+                type: object
                 properties:
                   data:
                     type: array
@@ -723,6 +724,7 @@ components:
           type: string
           format: uri
     Problem:
+      type: object
       xml:
         name: problem
         namespace: urn:ietf:rfc:7807
@@ -872,9 +874,10 @@ components:
         source:
           unevaluatedProperties: false
           description: The payment source to take the payment from. This can be a card or a bank account. Some of these properties will be hidden on read to protect PII leaking.
-          anyOf:
+          oneOf:
             - title: Card
               description: A card (debit or credit) to take payment from.
+              type: object
               properties:
                 object:
                   type: string