Updated podspec.
Updated podspec.

ivulyov/RATreeView,Nirvana-icy/RATreeView,zuojx1013/RATreeView,AlexanderMazaletskiy/RATreeView,wenxp/RATreeView,tuanphung/RATreeView,benzhipeng/RATreeView,ideacp/RATreeView,200895045/RATreeView,cnbin/RATreeView,chenkaige/RATreeView,treejames/RATreeView