Issues with the action? Make sure you update your <version> in the pom.xml If you don't you'll get Access Denied (403) errors since packages at a specific version are immutable
Want to debug connections between github packages and your local machine? Try this gist on how to do it with fiddler https://gist.github.com/seansaleh/9aff36c4307e7f2065b27fe0c62105d8
Some other repo's to reference:
https://github.com/ribasco/test-workflow
https://github.com/shibme/maven-test
https://github.com/avides/packages-example-for-support
https://github.com/GamebreakingStudios/github-package-registry-example
Or Just try this search on github: https://github.com/search?p=1&q=%22maven.pkg.github.com%22+%22maven-source-plugin%22&type=Code