pagerduty v1 api is decommissioned

[yiwensong]

since pagerduty v1 api is decommissioned, the support for that API should be dropped and v2 should be the default.

[cugini-dbx]

Sorry for the late reply! This sounds totally reasonable. Going to be doing a bugfix release this week, but I'll queue that up for the next minor version bump soon.