Hi, team! Thank you for your efforts in making and supporting this repository!

I've seen a request to make docker-letsencrypt-nginx-proxy-companion respect the connected networks in order to have multiple separate nginx-proxy installations running on the same host. It is useful for cases when you have multiple external IP addresses on the host and you need to distribute running services between them.

Currently, jwilder/nginx-proxy generates vhosts.conf only out of containers that are in the same network with it, but docker-letsencrypt-nginx-proxy-companion tries to generate certificates for all running containers.

Having a single docker-letsencrypt-nginx-proxy-companion for all nginx-proxy containers might be a solution, but companion can manage only a single nginx proxy service, but going this way makes the proxy service not complementary: I have to run either multiple nginx-proxies and deploy letsencrypt-companion somewhere else.

I suggest to limit letsencrypt_service_data.tmpl to nginx containters that share the same network only. I've added this thing a few years ago and it works in production for a long time without any issues.

If you think this change is acceptable, I can create a pull request.