[Go] Array of nullable items not modeled as a slice of pointers

If I run the following spec against the online API:

openapi: "3.0.3"
info:
  title: Example
  version: "0.0.0"
paths: {}
components:
  schemas:
    A:
      type: object
      properties:
        strs:
          type: array
          items:
            type: string
            nullable: true

it produces the following model:

type A struct {
	Strs []string `json:"strs,omitempty"`
}

where strs should probably be a []*string.

Some inspection of the code suggests the problem is that AbstractGoCodegen.getTypeDeclaration does not deal with nullability at all, when in reality it must because it is recursive.

Start at AbstractGoCodegen.getTypeDeclaration and reproduce the supplied OpenAPI 3.0.3 schema to trace how nullable array items are modeled. Done means the generated A model represents strs as []*string rather than []string, with appropriate coverage for the recursive nullability case.