code: function getPubkeyHex(privkey_hex) {
     let privkey = BigInteger.fromBuffer( decodePrivateKey(privkey_hex) );
     let public_key = new bitcoinjs.ECPair(privkey);
  
     public_key.compressed = false;
     let public_key_str = public_key.getPublicKeyBuffer().toString('hex');
     return public_key_str;
  }
docs: /*
  Get a *uncompressed* public key (hex) from private key