Configure Nginx with Github Webhooks and secret

Question

I have been looking for a way to configure my Nginx to listen to POST requests of webhooks from Github.

I configured a new Webhook in Github as follows:

Payload URL: https://myUrl/payload Secret: thisisthesecret

My goal is to tell Nginx: once you receive POST request (Github webhook in my case), if the header you got matches "thisisthesecret" then return "OK" and put the payload under https://myUrl/payload

Except for this example I couldn't find any implementation of it online so I am reaching out to your assistance.

This is my current nginx.config file:

user  nginx;
worker_processes  1;

error_log  /var/log/nginx/error.log warn;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    keepalive_timeout  65;

    #gzip  on;

    include /etc/nginx/conf.d/*.conf;
}