kataconda playground is no longer available

[Bo Liu]

In https://kubernetes.feisky.xyz/introduction/cluster#katacoda-playground, kataconda playground is listed as one of the online environment for playing with kubernetes. CLick the link it will take you to this notice says Kataconda has been permanently closed.

The annoucement from O'Reily about closing Kataconde: https://www.oreilly.com/online-learning/leveraging-katacoda-technology.html

[Pengfei Ni]

thanks for reporting, updated contents.