Fixes: UncheckedJSONSchemaType ['type'] field does not support 'array', 'object', and 'null' in an array

[utrumo]

What issue does this pull request resolve? Fixes: UncheckedJSONSchemaType ['type'] field does not support 'array', 'object', and 'null' in an array #2518 What changes did you make? Fixed the type UncheckedJSONSchemaType.

Is there anything that requires more attention while reviewing? No, the library is working unchanged.

[ezpuzz]

This solved my issue in for a required type: ['string', 'null'] field.