Bump GoogleAnalytics-iOS-SDK to 3.0.3c

The GoogleAnalytics team has reworked the GoogleAnalytics-iOS-SDK to remove the dependency on AdSupport. The spec update was merged into [CocoaPods / Specs](https://github.com/CocoaPods/Specs) with PR [#8346](https://github.com/CocoaPods/Specs/pull/8346). This should solve issue #94