chore: may myokx to okx - it's just an alias for european users

Author: xmatthias

freqtrade/exchange/common.py

@@ -47,6 +47,7 @@ def _get_logging_mixin():
     "binanceje": "binance",
     "binanceusdm": "binance",
     "okex": "okx",
+    "myokx": "okx",
     "gateio": "gate",
     "huboi": "htx",
 }