Update elliptic-curve and digest

[daxpedda]

This builds on RustCrypto/traits#883.

The changes are minimal, a lot of added where bounds because of Hmac and changed Inverts associated type Output to CtOption<T>.

To separate or not to separate

Currently there is an issue with having ring-compat reference a different version of signature then what the workspace has: ``` error: failed to select a version for `signature`. ... required by package `ecdsa v0.13.3` ... which satisfies dependency `ecdsa = "^0.13"` of package `ring-compat v0.4.0` ... which satisfies dependency `ring-compat = "^0.4"` of package `ed25519 v1.4.0-pre (**/ed25519)` versions that meet the requirements `>=1.3.1, <1.5` are: 1.4.0, 1.3.2, 1.3.1

all possible versions conflict with previously selected packages.

previously selected package signature v1.5.0
... which satisfies dependency signature = "^1.5" (locked to 1.5.0) of package ecdsa v0.13.4 (**/ecdsa)

failed to select a version for signature which could resolve this conflict

I circumvented this by updating ring-compat, but that is something I don't want to do because I have no clue what I'm doing there:
https://github.com/RustCrypto/ring-compat/compare/master...khonsulabs:ecdsa-digest

So I say either I actually manage to update rust-compat with some feedback, or we find a way to resolve this, for example by removing ed25519 from the workspace. Like is done in the traits repository with elliptic-curve. I would prefer not updating rust-compat.
</details>
I decided to go ahead and exclude ed25519 from the workspace. This should make updating easier.

[tarcieri]

@daxpedda you should be able to update this to use https://github.com/RustCrypto/traits.git as the upstream repo, and pin the elliptic-curve version to v0.12.0-pre

[daxpedda]

Done.

[tarcieri]

elliptic-curve v0.12.0-pre.0 has been released to crates.io.

Note that MSRV is now 1.57.

[daxpedda]

I had to change the CI a bit because I excluded ed25519 from the workspace, I hope that's alright.

[tarcieri]

Why did you need to exclude it from the workspace?

All three crates in the workspace are 2021 edition crates.

[daxpedda]

Currently there is an issue with having ring-compat reference a different version of signature then what the workspace has:

error: failed to select a version for `signature`.
    ... required by package `ecdsa v0.13.3`
    ... which satisfies dependency `ecdsa = "^0.13"` of package `ring-compat v0.4.0`
    ... which satisfies dependency `ring-compat = "^0.4"` of package `ed25519 v1.4.0-pre (**/ed25519)`
versions that meet the requirements `>=1.3.1, <1.5` are: 1.4.0, 1.3.2, 1.3.1

all possible versions conflict with previously selected packages.

  previously selected package `signature v1.5.0`
    ... which satisfies dependency `signature = "^1.5"` (locked to 1.5.0) of package `ecdsa v0.13.4 (**/ecdsa)`

failed to select a version for `signature` which could resolve this conflict

I circumvented this by updating ring-compat, but that is something I don't want to do because I have no clue what I'm doing there:
RustCrypto/ring-compat@master...khonsulabs:ecdsa-digest

So I say either I actually manage to update rust-compat with some feedback, or we find a way to resolve this, for example by removing ed25519 from the workspace. Like is done in the traits repository with elliptic-curve. I would prefer not updating rust-compat.

I don't know any way to resolve it otherwise.

[tarcieri]

Aha, makes sense