Bug 1505084: update the KumaScript Dockerfile to install Node 10.14.2
Bug 1505084: update the KumaScript Dockerfile to install Node 10.14.2

https://github.com/mdn/kumascript/pull/1008 updates KumaScript to
use Node 10 instead of Node 8. This patch updates the KumaScript
Dockerfile in the Kuma repo to install Node 10 in the KumaScript image.

a2sheppy/kuma,SphinxKnight/kuma,a2sheppy/kuma,a2sheppy/kuma,Elchi3/kuma,SphinxKnight/kuma,jwhitlock/kuma,jwhitlock/kuma,SphinxKnight/kuma,escattone/kuma,a2sheppy/kuma,mozilla/kuma,Elchi3/kuma,escattone/kuma,mozilla/kuma,Elchi3/kuma,SphinxKnight/kuma,mozilla/kuma,mozilla/kuma,Elchi3/kuma,mozilla/kuma,a2sheppy/kuma,jwhitlock/kuma,SphinxKnight/kuma,jwhitlock/kuma,jwhitlock/kuma,SphinxKnight/kuma,escattone/kuma,Elchi3/kuma