Gumroad sale trigger

## Connection to [MailerLite]({{ $env.WEBHOOK_URL }} newsletter 
### Requirements
- A [Mailerlite]({{ $env.WEBHOOK_URL }} account
- A subscriber group created
- Generate a new API from the Integrations menu

### Set up
- You will first need to create the subscriber with a simple Mailer lite node
- In the second node call the endpoint to [assign that same subscriber to the group]({{ $env.WEBHOOK_URL }} you created manually on Mailerlite. For example, we named the group "Gumroad"
- To get the group id, we ran a node that calls the ["list groups" endpoint]({{ $env.WEBHOOK_URL }} and we appended it to the url.