fix typo

Author: AndreasHeine

README.md

@@ -9,7 +9,7 @@ http://freeopcua.github.io/, https://github.com/FreeOpcUa/python-opcua
 
 [![PyPI Package](https://badge.fury.io/py/opcua.svg)](https://badge.fury.io/py/opcua)
 
-**The library is in maintenance mode. The plan is now to focus on the asyncio version of this library: [python-asyncio](https://github.com/FreeOpcUa/opcua-asyncio) which also has a [sync-wrapper](https://github.com/FreeOpcUa/opcua-asyncio/blob/master/asyncua/sync.py), with very few changes in API**
+**The library is in maintenance mode. The plan is now to focus on the asyncio version of this library: [opcua-asyncio](https://github.com/FreeOpcUa/opcua-asyncio) which also has a [sync-wrapper](https://github.com/FreeOpcUa/opcua-asyncio/blob/master/asyncua/sync.py), with very few changes in API**
 
 **PR to fix bugs to python-opcua are welcome, but if you want to write new fancy features or architectural changes, please look at opcua-asyncio**