replace this character " ‘ " with this " ' " in your podfile and try to install again.
it's happen to me when I copy pod line from somewhere else (like Evernote), some text editors automatically change this character. Usually it's like this :
pod 'AFNetworking', '~> 2.0'
but when I take from other editor, it could be like this :
pod ‘AFNetworking‘, ‘~> 2.0‘
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