Support serde_valid 0.16

Author: richardwhiuk

Cargo.toml

@@ -32,7 +32,7 @@ conversion = ["frunk", "frunk_derives", "frunk_core", "frunk-enum-core", "frunk-
 base64 = "0.13"
 serde = { version = "1.0.119", optional = true, features = ["derive"] }
 serde_json = { version = "1.0", optional = true }
-serde_valid = { version = "0.15", optional = true }
+serde_valid = { version = ">= 0.15, < 0.17", optional = true }
 regex = { version = "1", optional = true }
 paste = { version = "1", optional = true }
 hyper = "0.14"