cbor: rename crate to sk-cbor

In anticipation of publishing to crates.io, which already has a `cbor`
crate.

fuzz/fuzz_helper/src/lib.rs

@@ -29,6 +29,7 @@ use ctap2::ctap::hid::{ChannelID, CtapHid, HidPacket, Message};
 use ctap2::ctap::status_code::Ctap2StatusCode;
 use ctap2::ctap::CtapState;
 use libtock_drivers::timer::{ClockValue, Timestamp};
+use sk_cbor as cbor;
 
 const COMMAND_INIT: u8 = 0x06;
 const CHANNEL_BROADCAST: ChannelID = [0xFF, 0xFF, 0xFF, 0xFF];