required() seems to be getting ignored

[KieranHarper]

Noticed when trying to use the sample code example to define a type from a schema:

const schema = Joi.array()
  .items({
    id: Joi.number().integer().required(),
    email: Joi.string().email()
  })
  .required()

type T = Joi.Literal<typeof schema>

It seems to be ignoring required(), producing my results below instead:

My versions:

"typesafe-joi": "^2.0.6",
"@hapi/joi": "^15.1.1",
"typescript": "^3.5.1"