Update play store icon

README.md

@@ -5,10 +5,7 @@ Java library used to read and extract public data from NFC EMV credit cards.<br/
 <br/>
 Android sample app available on Play store.
 
-<a href="https://play.google.com/store/apps/details?id=com.github.devnied.emvnfccard">
-  <img alt="EMV NFC paycard reader Demo on Google Play"
-         src="http://developer.android.com/images/brand/en_generic_rgb_wo_60.png" />
-</a>
+<a href="https://play.google.com/store/apps/details?id=com.github.devnied.emvnfccard&utm_source=global_co&utm_medium=prtnr&utm_content=Mar2515&utm_campaign=PartBadge&pcampaignid=MKT-AC-global-none-all-co-pr-py-PartBadges-Oct1515-1"><img height="60px" alt="Get it on Google Play" src="https://play.google.com/intl/en_us/badges/images/apps/en-play-badge.png" /></a>
 
 ### Getting started