Bump serdect to v0.4 (#584)

Author: tarcieri

Cargo.lock

@@ -25,7 +25,7 @@ zeroize = { version = "1.5", features = ["alloc"] }
 # optional dependencies
 pkcs1 = { version = "0.8.0-rc.3", optional = true, default-features = false, features = ["alloc", "pem"] }
 pkcs8 = { version = "0.11.0-rc.6", optional = true, default-features = false, features = ["alloc", "pem"] }
-serdect = { version = "0.3.0", optional = true }
+serdect = { version = "0.4", optional = true }
 sha1 = { version = "0.11.0-rc.2", optional = true, default-features = false, features = ["oid"] }
 spki = { version = "0.8.0-rc.4", optional = true, default-features = false, features = ["alloc"] }
 sha2 = { version = "0.11.0-rc.2", optional = true, default-features = false, features = ["oid"] }