Tweak keypress sound volume default value of Grouper

Bug: 6499913
Change-Id: I645e40ad02c14b463854f91ec45c1be9c598e46e
diff --git a/java/res/values/keypress-volumes.xml b/java/res/values/keypress-volumes.xml
index 1bec6a3..3b433e4 100644
--- a/java/res/values/keypress-volumes.xml
+++ b/java/res/values/keypress-volumes.xml
@@ -23,5 +23,6 @@
         <item>herring,0.5</item>
         <item>tuna,0.5</item>
         <item>stingray,0.4</item>
+        <item>grouper,0.3</item>
     </string-array>
 </resources>