l10n README.md: update client configuration URL
l10n README.md: update client configuration URL
koreader/koreader,Markismus/koreader,NiLuJe/koreader,NiLuJe/koreader,poire-z/koreader,pazos/koreader,lgeek/koreader,poire-z/koreader,Frenzie/koreader,mwoz123/koreader,Hzj-jie/koreader,Frenzie/koreader,koreader/koreader,robert00s/koreader,apletnev/koreader,houqp/koreader,mihailim/koreader