v2.0.0

• Change pae::pae to borrow a slice of slices (&[&[u8]]) instead of taking ownership of a Vec<Vec>.
• High-level functions like validate_local_token and validate_public_token now take the key by reference.
• The reference to key passed as argument to v1::public::public_paseto is not longer taken as mutable.
• tokens::PasetoBuilder methods have been changed to only take references
• Support for the time crate has been added with a feature, this should not be used in conjunction with chrono.
• Create better error messages to hopefully be less user hostile.
• update dependencies.
• versions now have a "build number" to indicate what upstream version they track.