Option to force DNS resolution using external DNS provider

[g3rmanaviator]

1. What's the feature?
   Toggle to select between native OS DNS resolution (i.e. DNS server configured by the operating system) or
   external provider or external IPs.

2. Extra information?
   When using split DNS a host or domain will typically resolve to a private RFC1918 address because the internal DNS server resolves
   to the private IP of 10.x.x.x or 192.168.x.x instead of the public NAT IP.
   To overcome this it would be ideal to be able to tell the updater which DNS server to use to verify what the host or domain
   currently resolves to. For example:

-Resolve current IP using host DNS
-Resolve current IP using (Google (8.8.8.8), Cloudflare (1.1.1.1), or Quad9 (9.9.9.9))

[g3rmanaviator]

Can be accomplished by passing "--dns" option to container.

[qdm12]

Indeed!

Or

  dns: 1.1.1.1

for docker-compose.yml files.