Bump signature dependency to v3 (#693)

Release PR: RustCrypto/traits#2400

Author: tarcieri

Cargo.lock

@@ -19,7 +19,7 @@ crypto-bigint = { version = "0.7", default-features = false, features = ["zeroiz
 crypto-primes = { version = "0.7", default-features = false }
 digest = { version = "0.11", default-features = false, features = ["alloc", "oid"] }
 rand_core = { version = "0.10", default-features = false }
-signature = { version = "3.0.0-rc.10", default-features = false, features = ["alloc", "digest", "rand_core"] }
+signature = { version = "3", default-features = false, features = ["alloc", "digest", "rand_core"] }
 zeroize = { version = "1.8", features = ["alloc"] }
 
 # optional dependencies