Arrays without maxItems,minItems properties get 0 in schema

[pavelmaliy]

When struct property is an array, in the generated schema you get:
maxItems: 0, minItems: 0
It should be without those properties.

type MyType struct {
	SomeArray     []int                 `json:"someArray"`
}

This bug started to occur when upgrading from v0.8.0 -> v0.12.0

Thanks.