Bump version to 5.13.8

app/build.gradle

@@ -55,8 +55,8 @@ protobuf {
     }
 }
 
-def canonicalVersionCode = 859
-def canonicalVersionName = "5.13.7"
+def canonicalVersionCode = 860
+def canonicalVersionName = "5.13.8"
 
 def postFixSize = 100
 def abiPostFix = ['universal'   : 0,