Creating Partner breaking with Country struct

[wynandmeintjes]

In version github.com/dubinc/dub-go v0.17.1 the partner was created with a country struct

	// The partner's country of residence. Must be passed as a 2-letter ISO 3166-1 country code. Learn more: https://d.to/geo
	Country *Country `json:"country,omitempty"`

whereas with github.com/dubinc/dub-go v0.18.0 the partner now gets created with a country *string

	// The partner's country of residence. Must be passed as a 2-letter ISO 3166-1 country code. See https://d.to/geo for more information.
	Country *string `json:"country,omitempty"`

This is definitely a nice improvement since I no longer need to map country codes to your country structs. That said, it feels like it should have been released as a breaking change, or at the very least mentioned in the release notes as part of the migration.

[wynandmeintjes]

@steven-tey - do you have plans to improve release notes ? I am thinking of folks (myself included) using renovate to check for dependencies and this was marked as a minor update without any comments.