Fix error handling for decoding errors

main.py

@@ -34,7 +34,7 @@ def get_decoded_header(value):
     for item in decoded_header_items:
         decoded_item = item[0].decode(item[1]) if item[1] is not None else item[0]
         if isinstance(decoded_item, bytes):
-            decoded_item = decoded_item.decode('ascii')
+            decoded_item = decoded_item.decode('ascii', 'replace')
         decoded_header_value += decoded_item
     return decoded_header_value