update podspec 5.3
update podspec 5.3

hanton/MessageDisplayKit,02002love/MessageDisplayKit,PutADing/MessageDisplayKit,xhzengAIB/MessageDisplayKit,feijilei/MessageDisplayKit,rahul-apple/MessageDisplayKit,feijilei/MessageDisplayKit,02002love/MessageDisplayKit,mxxiv/MessageDisplayKit,mxxiv/MessageDisplayKit,rahul-apple/MessageDisplayKit,xhzengAIB/MessageDisplayKit,PutADing/MessageDisplayKit,hanton/MessageDisplayKit