Update README.md

Fix GooglePlay download's link

Author: kimkevin

README.md

@@ -29,7 +29,7 @@ It's easy to interact with the Toolbar introduced in Android 5.0 Lollipop  and m
 
 ### Download from Google Play
 
-[![Get it on Google Play](https://developer.android.com/images/brand/en_generic_rgb_wo_45.png)](https://play.google.com/store/apps/details?id=com.github.ksoichiro.android.observablescrollview.samples2)
+<a href="https://play.google.com/store/apps/details?id=com.github.ksoichiro.android.observablescrollview.samples2"><img alt="Get it on Google Play" src="https://play.google.com/intl/en_us/badges/images/generic/en-play-badge.png" height="50px"/></a>
 
 Please note that the app on the Play store is not always the latest version.