docker: update go version 1.7 -> 1.11
docker: update go version 1.7 -> 1.11



bookingcom/bosun,bookingcom/bosun,bookingcom/bosun,bosun-monitor/bosun,bosun-monitor/bosun,bookingcom/bosun,bosun-monitor/bosun,bosun-monitor/bosun,bookingcom/bosun,bookingcom/bosun,bosun-monitor/bosun,bosun-monitor/bosun