Update gson version used in the Maven example
diff --git a/UserGuide.md b/UserGuide.md
index f7b30bc..da3b2f0 100644
--- a/UserGuide.md
+++ b/UserGuide.md
@@ -79,7 +79,7 @@
     <dependency>
       <groupId>com.google.code.gson</groupId>
       <artifactId>gson</artifactId>
-      <version>2.7</version>
+      <version>2.8</version>
       <scope>compile</scope>
     </dependency>
 </dependencies>