Bump version to 4.61.6

Author: greyson-signal

app/build.gradle

@@ -80,8 +80,8 @@ protobuf {
     }
 }
 
-def canonicalVersionCode = 646
-def canonicalVersionName = "4.61.5"
+def canonicalVersionCode = 647
+def canonicalVersionName = "4.61.6"
 
 def postFixSize = 10
 def abiPostFix = ['universal'   : 0,