Update digest requirement from 0.9 to 0.10

Updates the requirements on [digest](https://github.com/RustCrypto/traits) to permit the latest version.
- [Release notes](https://github.com/RustCrypto/traits/releases)
- [Commits](https://github.com/RustCrypto/traits/compare/digest-v0.9.0...digest-v0.10.0)

---
updated-dependencies:
- dependency-name: digest
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Cargo.toml

@@ -20,7 +20,7 @@ features = ["nightly"]
 [dependencies]
 blake2b_simd = "0.5"
 byteorder = "1.4"
-digest = "0.9"
+digest = "0.10"
 jubjub = "0.8"
 rand_core = "0.6"
 serde = { version = "1", optional = true, features = ["derive"] }