Update xchacha.rs

Author: nstilt1

rand_chacha/src/xchacha.rs

@@ -9,7 +9,7 @@ use cipher::{
 };
 
 #[cfg(feature = "zeroize")]
-use cipher::zeroize::ZeroizeOnDrop;
+use zeroize::ZeroizeOnDrop;
 
 /// Nonce type used by XChaCha variants.
 pub type XNonce = GenericArray<u8, U24>;