Guide needs updating

[Swordopolis]

The guide references installing HypriotOS v1.4.0, which came out more than two years ago, and does not have support for newer models like the Raspberry Pi 4.

Attempting the same steps with a newer version of HypriotOS results in issues like:
CoreDNS CrashLoopBackOff - I encountered this when using HypriotOS v1.11.2 on Pi 4. The newer version of Docker doesn't seem to play well with k8s

Once I can get k8s to work on HypriotOS for Raspberry Pi 4 I'm happy to contribute myself, but so far I haven't gotten all the way to a working cluster.