Use new Keypair API

Stop using deprecated API in favour of the new one.

Author: tcharding

bitcoin/examples/taproot-psbt.rs

@@ -746,7 +746,7 @@ fn sign_psbt_taproot(
     sighash_type: TapSighashType,
     secp: &Secp256k1<secp256k1::All>,
 ) {
-    let keypair = secp256k1::Keypair::from_seckey_slice(secp, secret_key.as_ref()).unwrap();
+    let keypair = secp256k1::Keypair::from_seckey_byte_array(secp, secret_key.secret_bytes()).unwrap();
     let keypair = match leaf_hash {
         None => keypair.tap_tweak(secp, psbt_input.tap_merkle_root).to_keypair(),
         Some(_) => keypair, // no tweak for script spend

bitcoin/src/bip32.rs

@@ -745,7 +745,7 @@ impl Xpriv {
     /// Constructs a new BIP-0340 keypair for Schnorr signatures and Taproot use matching the internal
     /// secret key representation.
     pub fn to_keypair<C: secp256k1::Signing>(self, secp: &Secp256k1<C>) -> Keypair {
-        Keypair::from_seckey_slice(secp, &self.private_key[..])
+        Keypair::from_seckey_byte_array(secp, self.private_key.secret_bytes())
             .expect("BIP-0032 internal private key representation is broken")
     }