Deprecated link in the README.md

[MS893]

Expected Behavior

When clicking on the Google Play services SDK link, we should go to the correct page

Actual Behavior

When clicking on the link, this page is displayed : Service Unavailable

Steps to Reproduce the Problem

1. Just click on the link !

It is necessary to upadte the link, or the steps in the setup :

Set Up
Install the Android SDK.
Download and configure the Google Play services SDK. <-------