Update HPGrowingTextView.podspec
Update HPGrowingTextView.podspec

Closes issue #34
HansPinckaers/GrowingTextView,happy-tanuki/GrowingTextView,perrystreetsoftware/GrowingTextView,Kingside/GrowingTextView,alexeylang/GrowingTextView,shenhzou654321/GrowingTextView,zuojx1013/GrowingTextView,ywzw2013/GrowingTextView,jagreenwood/GrowingTextView,mabuward90/GrowingTextView,Meihualu/GrowingTextView