Enforce documented /pets pagination size limit (OAI#3070)

Author: TheTeaCat

examples/v3.0/petstore.yaml

@@ -20,6 +20,7 @@ paths:
           required: false
           schema:
             type: integer
+            maximum: 100
             format: int32
       responses:
         '200':
@@ -96,6 +97,7 @@ components:
           type: string
     Pets:
       type: array
+      maxItems: 100
       items:
         $ref: "#/components/schemas/Pet"
     Error: