Add support for GitHub Enterprise
Add support for GitHub Enterprise

* Capture the request IP before entering the for loop, rename variable fromip
  to request_ip for uniqueness in any future work with IP addresses.

* Look for environment variable GHE_ADDRESS and set it as the hook_blocks list
  if present.

* Fallback to the public API if GHE_ADDRESS is not set.

ftomassetti/diagrams-webhook