docs(api): add url parameter to config method (#278)

Author: bapu88

docs/content/en/api/query-builder-methods.md

@@ -243,6 +243,7 @@ Configuration of HTTP Instance.
 ```js
 await Model.config({
  method: 'PATCH',
+ url: 'foo-bar',
  header: { /* ... */ },
  data: { foo: 'bar' }
 }).save()