Refresh requirements and dependencies

[diizzyy]

It's almost a year since last recent, perhaps it's time to refresh requirements and deps to ensure future compatibility with later versions of Rust?

[sdroege]

Is there any specific dependency you'd like to see updated?

bitflags could be updated to version 2 but I think that's going to break API.

Updating quickcheck/criterion needs a little bit more work.

[diizzyy]

Nothin specific, mainly a concern of "bitrot" of old dependencies and newer versions of Rust compiler. Thanks for looking into it.