chore: Update gson in test projects (#612)

Signed-off-by: sheche <sheche@microsoft.com>

test/java9/pom.xml

@@ -17,7 +17,7 @@
     <dependency>
       <groupId>com.google.code.gson</groupId>
       <artifactId>gson</artifactId>
-      <version>2.7</version>
+      <version>2.8.9</version>
     </dependency>
   </dependencies>