Use recent method for macro import

src/constants.rs

@@ -1,5 +1,7 @@
 // https://developers.yubico.com/PIV/Introduction/Yubico_extensions.html
 
+use hex_literal::hex;
+
 pub const RID_LENGTH: usize = 5;
 
 // top nibble of first byte is "category", here "A" = International

src/container.rs

@@ -1,4 +1,6 @@
 use core::convert::TryFrom;
+
+use hex_literal::hex;
 // use flexiber::{Decodable, Encodable};
 
 pub struct Tag<'a>(&'a [u8]);

src/lib.rs

@@ -7,9 +7,6 @@ extern crate log;
 #[cfg(feature = "delog")]
 delog::generate_macros!();
 
-#[macro_use(hex)]
-extern crate hex_literal;
-
 pub mod commands;
 pub use commands::Command;
 pub mod constants;

src/piv_types.rs

@@ -1,6 +1,7 @@
 use core::convert::{TryFrom, TryInto};
 
 use flexiber::Encodable;
+use hex_literal::hex;
 use serde::{Deserialize, Serialize};
 
 /// According to spec, a PIN must be 6-8 digits, padded to 8 bytes with 0xFF.