salsa20: do not use zeroize default features to prevent alloc inclusion (#189)

Author: Wassasin

salsa20/Cargo.toml

@@ -12,7 +12,7 @@ edition = "2018"
 
 [dependencies]
 cipher = "0.2"
-zeroize = { version = "1", optional = true }
+zeroize = { version = "1", default-features = false, optional = true }
 
 [dev-dependencies]
 cipher = { version = "0.2", features = ["dev"] }