updated contributing [ci skip]
updated contributing [ci skip]

ccxt/ccxt,thijstriemstra/ccxt,ccxt/ccxt,ccxt/ccxt,aiueogawa/ccxt,thijstriemstra/ccxt,aiueogawa/ccxt,ccxt/ccxt,ccxt/ccxt,aiueogawa/ccxt,tritoanst/ccxt,aiueogawa/ccxt,tritoanst/ccxt,thijstriemstra/ccxt,tritoanst/ccxt,thijstriemstra/ccxt,tritoanst/ccxt