A simple webhook to filter and forward requests to portainer for a specific branch.
Content type is json.
The webhook url would be http://yourhost:3473?branch=master&uuid=abc-def-ghi-hjk where uuid is your portainer webhook uuid after /api/stacks/webhooks/ and branch is the desired branch to cause invocations.
PORTAINER_URL=http://sub.domain.tld
SECRET_KEY=abcdefghijklmnopqrstuvwxyz1234567890 # GitHub webhook secret key