instability-v0.3.3

Added

• add stable macro (#14)
• use doc(cfg) - Note: this requires #![feature(doc_cfg)] to be added to your lib.rs (consider feature flagging this e.g. #![cfg_attr(docsrs, feature(doc_cfg))])

Fixed

• tests (#13)
• change master to main in lib.rs

Other

• bump msrv to 1.63
• use proc_macro2 and add tests
• use darling instead of manual parsing for better error messages on attributes