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>com.amazon.jenkins.fleet</groupId>
<artifactId>ec2-fleet</artifactId>
<version>4.2.3.539.v8fedff2a_81c3</version>
</dependency>