Update to generic-array 1.0

[rukai]

Generic-array recently released 1.0 https://github.com/fizyk20/generic-array/blob/master/CHANGELOG.md
I would love to see this dependency updated.
It does however require an MSRV of 1.65 which might be a blocker for this project.

[brxken128]

I think the plan is to migrate over fully to hybrid-array, so there's likely no point.

hybrid-array work has already started iirc, and aims to ease the move from GA to const generics (once Rust has adequate support for all of RustCrypto's needs).

[tarcieri]

We're migrating to hybrid-array, which is a simple wrapper around core arrays which uses significantly less unsafe code and deeply integrates with const generics.

See #944

[rukai]

oh excellent! Sounds good to me 👍