This is a legacy library with functionality provided by newer versions of Java.
This project is published using the guide found here and the guide on how to setup signing with pgp2.
The changes required are in the .pom file which has the required components.
The release was basically performed by running the command mvn deploy. This will either release your version (if the version number does not end in -SNAPSHOT) or do a proper release in case you have a non snapshot version in your pom.