Update Sakai maven plugin to 1.2.0

Plugin version is outdated. Update to 1.2.0.

<plugin>
<inherited>true</inherited>
<groupId>org.sakaiproject.maven.plugins</groupId>
<artifactId>sakai</artifactId>
<version>1.1</version>
<extensions>true</extensions>
<configuration>
<deployDirectory>
${maven.tomcat.home}
</deployDirectory>
<warSourceDirectory>
${basedir}/src/main/webapp
</warSourceDirectory>
</configuration>
</plugin>