Fix example response reference
`GET /pets/{petId}` returns a pet, not pets.
MODIFY
examples/v3.0/petstore.yaml
examples/v3.0/petstore.yaml
@@ -72,7 +72,7 @@ paths:
content:
application/json:
schema:
- $ref: "#/components/schemas/Pets"
+ $ref: "#/components/schemas/Pet"
default:
description: unexpected error
content:

Fix example response reference (#1670)

`GET /pets/{petId}` returns a pet, not pets.