[enh] #140 update dependencies in README.md

README.md

@@ -28,7 +28,7 @@ It is currently used by following programs:
 
 ## Requirements
 - Python >= 3.6.8
-- [aiohttp >= 3.6.3](https://pypi.org/project/aiohttp)
+- [websocket-client](https://pypi.org/project/websocket-client)
 - [jsonschema](https://pypi.org/project/jsonschema)
 - [pyPEG2](https://pypi.org/project/pyPEG2)
 - [attrs](https://pypi.org/project/attrs)