How do I validate the key of a object type schema | v3.0.4

I have my api.yaml like this, I want to validate that the lenght of the key of this map shouldn't be empty.
How do I do it with swagger itself. I tried the below, the code generated validates the value and not the key.

components:
  schemas:
    MyObject:
      properties:
        labels:
          title: labels
          type: object
          additionalProperties:
            type: string
            minLength: 1
            pattern: "^.+$"
          description: JSON dictionary of labels
          example:
            someKey: SomeValue
            someKey2: SomeValue2
          x-omitempty: false

Is there a way to validate the object (HashMap) key also ?

More info:
I am using GoLang and in go a map can have a empty string as a key, that what I want to avoid, by using swagger and generated server code itself.