Bump signature from 1.6.4 to 2.2.0 (#1911)

Bumps [signature](https://github.com/RustCrypto/traits) from 1.6.4 to 2.2.0.
- [Commits](https://github.com/RustCrypto/traits/commits/signature-v2.2.0)

---
updated-dependencies:
- dependency-name: signature
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Cargo.toml

@@ -187,7 +187,7 @@ serde_yaml = "0.9"
 serde_repr = "0.1"
 serde-name = "0.2"
 serde_with = { version = "2.1.0", features = ["hex"] }
-signature = "1.6.0"
+signature = "2.2.0"
 slip10_ed25519 = "0.1.3"
 strum = "^0.24"
 strum_macros = "^0.24"