Link needs an update

[Sa1Gur]

C, C++
A CBOR implementation in C is part of the RIOT operating system for constrained nodes 

Structure of the RIOT repository changed and link is not working.

[h3xx]

This file was removed from RIOT OS sometime in 2018, and I think it was moved to its own separate repo... I think.

Current README says the repo is unmaintained, but suggests using @jimsch/cn-cbor as a replacement.

I'm still not sure what the link should be nowadays.

[cabo]

cn-cbor came out of my original proof-of-concept implementation in 2013 (I wanted to make sure that there weren't any surprises when implementing CBOR before standardizing it). Jim Schaad has taken over maintenance of that. Unfortunately, Jim has passed recently, so we will have to find a new maintainer.

The RIOT implementation wasn't based on cn-cbor AFAIK. See RIOT-OS/RIOT#1415

[cabo]

It becomes more complicated, as Jim Schaad, whom I have handed over cn-cbor to, sadly has passed away.
So this construction site will stay open for a couple more weeks...