Gemfile: Update CocoaPods to ~>1.9.3.
Gemfile: Update CocoaPods to ~>1.9.3.

vector-im/riot-ios,vector-im/riot-ios,vector-im/riot-ios,vector-im/vector-ios,vector-im/riot-ios,vector-im/riot-ios,vector-im/riot-ios,vector-im/vector-ios,vector-im/vector-ios