Dependency on heptiolabs/healthcheck prevents custom handler paths

Line 12 in d7bef63

"github.com/heptiolabs/healthcheck"

This go package has not been contributed to in over 3 years and many customers are integrating tools to verify health checks for services and have standardized on /readyz /livez and the now deprecated /healthz in many cases (Ref: https://kubernetes.io/docs/reference/using-api/health-checks/ )

There has been a PR waiting in the Heptio repo for over a year that would allow for a custom path handler but no one is looking at PRs (REF: vmware-archive/healthcheck#25 (comment))