* Update go-pingdom to include results api
* Update all other dependencies as they were pinned to 2017

Pingdom rotates probes when doing checks from the same region,
so the city and country will change at each check. To avoid
exporting outdated metrics, as they are associated with labels
which may change if choose to gather detailed probe infos, we must
delete them, so we keep only one exported metric for a given check
ID.