How to change java version and web version on org.eclipse.wst.common.project.facet.core.xml under .settings dir of eclipse project

Modified web.xml to have below:

<web-app xmlns="http://java.sun.com/xml/ns/javaee" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
    http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0">
   <display-name>Archetype Created Web Application</display-name>
</web-app>

and add following plugins as maven 3 wants to have compiler

<plugins>
    <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.1</version>
        <configuration>
            <source>1.6</source>
            <target>1.6</target>
        </configuration>
    </plugin>
</plugins>