add donate button to README
add donate button to README

waruqi/xmake,waruqi/xmake,waruqi/xmake,tboox/xmake,tboox/xmake,tboox/xmake,tboox/xmake,waruqi/xmake,waruqi/xmake,tboox/xmake,tboox/xmake,tboox/xmake,waruqi/xmake,waruqi/xmake