Some information to get you up and running if you want to contribute to the development of this plugin.
Please make sure that you have a JDK 1.8 installed. The build won't work with more modern JDK versions.
You will also need to the most recent version of Maven 3 installed.
Run mvn clean package to build everything.
You can use the Maven HPI plugin to run a local Jenkins instance for testing. This local instance will have the most recent version of the Jira Cloud plugin from your local workspace installed already.
When you run mvn hpi:run, the plugin will install and run a Jenkins server into the /work folder and you can access it via http://localhost:8080/jenkins.
You can now follow the steps in the README to use the integration.