As a plugin developer you can use this plugin as dependency of your plugin by adding a dependency tag to your POM.
To add the latest version of this plugin as a maven dependency, use the following:
<dependency>
<groupId>io.jenkins.plugins</groupId>
<artifactId>material-theme</artifactId>
<version>0.5.2-rc100.6121925fe229</version>
</dependency>