Use tag

Mobile-Buy-SDK.podspec

 Pod::Spec.new do |s|
   s.name         = 'Mobile-Buy-SDK'
-  s.version      = '1.1.5'
+  s.version      = '1.2.0'
   s.summary      = 'Sell with Shopify in iOS apps'
   s.description  = 'Shopify’s Mobile Buy SDK makes it simple to sell physical products inside your mobile app. With a few lines of code, you can connect your app with the Shopify platform and let your users buy your products using Apple Pay or their credit card.'
   s.homepage     = 'https://developers.shopify.com/mobile-buy-sdk'
   s.license      = { :type => 'MIT', :file => 'LICENSE' }
   s.author       = 'Shopify Inc.'
   s.platform     = :ios, '8.0'
-  s.source       = { :git => 'https://github.com/Shopify/mobile-buy-sdk-ios.git', :branch => 'task/cocoapods' }
+  s.source       = { :git => 'https://github.com/Shopify/mobile-buy-sdk-ios.git', :tag => s.version }
   s.source_files = 'Mobile Buy SDK/Mobile Buy SDK/**/*.{h,m,mm}'
   s.exclude_files = 'Mobile Buy SDK/Mobile Buy SDK/Buy.h'
   s.public_header_files = 'Mobile Buy SDK/Mobile Buy SDK/**/*.{h}'