fix: enable vendorfield for htlc lock (#104)

Author: dated

crypto/transactions/builder/htlc_lock.py

@@ -6,14 +6,15 @@ class HtlcLock(BaseTransactionBuilder):
 
     transaction_type = TRANSACTION_HTLC_LOCK
 
-    def __init__(self, recipient_id, secret_hash, expiration_type, expiration_value, fee=None):
+    def __init__(self, recipient_id, secret_hash, expiration_type, expiration_value, vendorField=None, fee=None):
         """Create a timelock transaction
 
         Args:
             recipient_id (str): recipient identifier
             secret_hash (str): a hash of the secret. The SAME hash must be used in the corresponding “claim” transaction
             expiration_type (int): type of the expiration. Either block height or network epoch timestamp based
             expiration_value (int): Expiration of transaction in seconds or height depending on expiration_type
+            vendorField (str): value for the vendor field aka smartbridge
             fee (int, optional): fee used for the transaction (default is already set)
         """
         super().__init__()
@@ -30,6 +31,8 @@ def __init__(self, recipient_id, secret_hash, expiration_type, expiration_value,
             }
         }
 
+        self.transaction.vendorField = vendorField.encode() if vendorField else None
+
         if fee:
             self.transaction.fee = fee