Download the latest plugin from GoCD extensions site. You can get access to the commercial extensions site for GoCD by contacting us at firstname.lastname@example.org.
Copy the downloaded
<GO_SERVER_DIR>/plugins/externaland restart the GoCD Server.
GO_SERVER_DIR is usually
/var/lib/go-server on Linux and
C:\Program Files(x86)\Go Server on Windows. You can find the location of the GoCD Server installation here.