Create contributing.md (#9)

Author: Vahila

devel/contributing.md

@@ -0,0 +1,15 @@
+## Contributing
+
+Verify changes by running tests and building locally with the following command:
+
+```
+mvn verify
+```
+
+## Creating a New Release
+
+Familiarize yourself with [Jenkins Plugin Release Using GitHub Actions](https://www.jenkins.io/doc/developer/publishing/releasing-cd/).
+
+Changes should be made on a new branch. The new branch should be merged to the main branch via a pull request. Ensure that all of the CI pipeline checks and tests have passed for your changes.
+
+After the pull request has been approved and merged to main, run the [cd.yaml](https://github.com/jenkinsci/matlab-plugin/actions/workflows/cd.yaml) file to create a new release. This workflow will create a release under [Releases](https://github.com/jenkinsci/matlab-plugin/releases). Review the autogenerated release notes and update them as needed.