Webhook merge request body is empty

Summary

GitLab 11.6.0 (075f9609)

I created a new Webhook merge request and the body (POST data) is empty. I also created a push Webhook and it's also empty.

According to the docs (/help/user/project/integrations/webhooks) it must contains a JSON with data.

Steps to reproduce

Create a new Webhook

What is the current bug behavior?

(POST data) is empty.

What is the expected correct behavior?

A JSON with data must be received.

/label ~bug