fix play store link

README.md

@@ -2,7 +2,7 @@
 
 [<img src="http://www.android.com/images/brand/android_app_on_play_large.png" 
       alt="Download from Google Play" 
-      height="80">](https://play.google.com/store/apps/details?id=com.nextcloud.client")
+      height="80">](https://play.google.com/store/apps/details?id=com.nextcloud.client)
 
 [<img src="https://f-droid.org/badge/get-it-on.png"
       alt="Get it on F-Droid"