chore: update keyring to version 3

[anchpop]

What

This PR updates the dependency keyring to version 3, from version 1.2 before.

Why

Having such an old version of keyring was causing the SDK to have duplicate versions of many dependencies, because the old version of keyring was pulling in old versions of lots of other libraries.

For example, previously the SDK was depending on rustix 0.37 as well as rustix 0.38. It was also depending on two versions of cipher, two versions of aes, two versions of hmac, two versions of proc-macro-crate, two versions of toml, two versions of socket2, two versions of async-lock, two versions of fastrand, and two versions of nix.

After this PR, the SDK will only depend on one version of each of these libraries. This will speed up build times and probably make the binary slightly smaller. At least, I think it should, I didn't measure it. One potential issue is that this PR starts us vendoring openssl - but I have no idea how to avoid this (it seems like we get CI errors otherwise). On the other hand, it seems like a smaller problem than having so many duplicate dependencies, and I will put some more time into trying to figure out how to avoid it.

How Has This Been Tested?

cargo clippy and cargo test

Checklist:

• The title of this PR complies with Conventional Commits.
• I have edited the CHANGELOG accordingly. (not necessary I think)
• I have made corresponding changes to the documentation. (none necessary I think)