Do not use SSH URL for cloning
Do not use SSH URL for cloning

This allows non-GitHub users to easily clone the repository as well.
The SSH URL would require SSH authentication which in turn requires a
GitHub account and we should never require someone to have one to use
httpbin from source.

krissman/httpbin,postmanlabs/httpbin,ewdurbin/httpbin,kennethreitz/httpbin,Runscope/httpbin,krissman/httpbin,Runscope/httpbin,bradparks/httpbin__http_echo_service_for_testing_http_requests,postmanlabs/httpbin,pestanko/httpbin,bradparks/httpbin__http_echo_service_for_testing_http_requests,pestanko/httpbin,kennethreitz/httpbin,ewdurbin/httpbin