elliptic-curve: bump rand_core to 0.9.0

[baloo]

This pulls:

• Bump rand_core from 0.6.4 to 0.9.0 crypto-bigint#762
• Bump version to v0.7.0-pre crypto-bigint#765
• Bump rand to 0.9 zkcrypto/ff#122
• Bump to rust-random 0.9 zkcrypto/group#56

[newpavlov]

@tarcieri
BTW how important is dependency on ff and group crates for elliptic-curve and its downstream users?

[tarcieri]

@newpavlov extremely. They provide the traits that generic protocol implementations such as the ecdsa crate are written in terms of

[newpavlov]

I mean, why can't we define those traits in our crates? Judging by the commit history, development is not particularly active for both crates. And it seems a bit strange to unconditionally depend on third-party crates for such important piece of functionality.

[tarcieri]

I would rather work with @str4d first than try to vendor ff and group into elliptic-curve.

Among other problems there are already existing forks of those crates in e.g. ark-ff and if anything I would like to see those forks resolved so there actually are a common set of traits for the whole Rust elliptic curve ecosystem.

[newpavlov]

Maybe we should ask zkcrypto developers whether they would be open to transferring those crates under our umbrella?