fixed rubocop error

spec/unit/installer/analyzer_spec.rb

@@ -728,7 +728,7 @@ module Pod
           end.message.should.match /Unable to find host target for Pods-Today Extension. Please add the host targets for the extensions to the Podfile/
         end
 
-        it "raises when the extension calls use_frameworks!, but the host target does not" do
+        it 'raises when the extension calls use_frameworks!, but the host target does not' do
           podfile = Pod::Podfile.new do
             source SpecHelper.test_repo_url
             platform :ios, '6.0'