The package golang-github-hashicorp-serf 0.8.1+git20171021.c20a0b1~ds1-5 has been added to kali-rolling. It has been imported from Debian: https://tracker.debian.org/pkg/golang-github-hashicorp-serf -- More information about golang-github-hashicorp-serf: http://pkg.kali.org/pkg/golang-github-hashicorp-serf