Upgraded example to latest versions and verified it runs (fix #143)

Author: oliemansm

example/pom.xml

@@ -14,14 +14,15 @@
     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
-        <version>1.5.1.RELEASE</version>
+        <version>2.0.4.RELEASE</version>
         <relativePath/> <!-- lookup parent from repository -->
     </parent>
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
         <java.version>1.8</java.version>
+        <graphql-spring-boot-starter.version>5.0.2</graphql-spring-boot-starter.version>
     </properties>
 
     <dependencies>
@@ -47,22 +48,22 @@
         <dependency>
             <groupId>com.graphql-java</groupId>
             <artifactId>graphql-spring-boot-starter</artifactId>
-            <version>4.2.0</version>
+            <version>${graphql-spring-boot-starter.version}</version>
         </dependency>
         <dependency>
             <groupId>com.graphql-java</groupId>
             <artifactId>graphiql-spring-boot-starter</artifactId>
-            <version>4.2.0</version>
+            <version>${graphql-spring-boot-starter.version}</version>
         </dependency>
         <dependency>
             <groupId>com.graphql-java</groupId>
             <artifactId>voyager-spring-boot-starter</artifactId>
-            <version>4.2.0</version>
+            <version>${graphql-spring-boot-starter.version}</version>
         </dependency>
         <dependency>
             <groupId>com.graphql-java</groupId>
             <artifactId>graphql-java-tools</artifactId>
-            <version>5.1.0</version>
+            <version>5.2.3</version>
         </dependency>
     </dependencies>