Add header platform-name to openapi implementation

[gusthavosouza]

In order to use the openapi feature would be great to have the platform-name header as an option in the payment creation, or any other request that we might have to send it over.

Describe the solution you'd like

Adds the platform-name to the openapi.

[jfrojd-paytrail]

Good note, this is definitely something that's missing. We will look into it.