updated maven example to Java 11

Author: sandybrownlee

examples/maven-simple/pom.xml

@@ -10,8 +10,8 @@
     <url>http://www.example.com</url>
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <maven.compiler.source>1.7</maven.compiler.source>
-        <maven.compiler.target>1.7</maven.compiler.target>
+        <maven.compiler.source>11</maven.compiler.source>
+        <maven.compiler.target>11</maven.compiler.target>
     </properties>
     <dependencies>
         <dependency>