dependencies: replace json-simple with gson (#2358)

pom.xml

@@ -233,6 +233,11 @@
         <artifactId>htmlunit</artifactId>
         <version>${htmlunit.version}</version>
       </dependency>
+      <dependency>
+        <groupId>com.google.code.gson</groupId>
+        <artifactId>gson</artifactId>
+        <version>2.10</version>
+      </dependency>
       <dependency>
         <groupId>com.google.inject</groupId>
         <artifactId>guice</artifactId>