Potential buffer overflow in CBOR2 decoder

Summary Ever since https://github.com/agronholm/cbor2/pull/204 or specifically https://github.com/agronholm/cbor2/commit/387755eacf0be35591a478d3c67fe10618a6d542 was merged, I can create a reproducible crash when running the snippet under PoC on a current Debian bullseye aarm64 on a Raspberry Pi ...