fix(deps): Update plugin com.google.protobuf to v0.9.6

Author: cq-bot

build.gradle

@@ -1,6 +1,6 @@
 plugins {
     id 'application'
-    id 'com.google.protobuf' version '0.9.4'
+    id 'com.google.protobuf' version '0.9.6'
     // Generate IntelliJ IDEA's .idea & .iml project files
     id 'idea'
     id "maven-publish"