Add support for publishing packages to github

[ThomasThelen]

Fix for #40

This PR adds a GitHub workflow file that creates the package in GitHub. Note that to read/download packages from GitHub, users will need to provide GitHub credentials (downside of GH vs Maven).

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[jmr]

Note that to read/download packages from GitHub, users will need to provide GitHub credentials (downside of GH vs Maven).

Why did you pick GH over Maven?

[ThomasThelen]

Note that to read/download packages from GitHub, users will need to provide GitHub credentials (downside of GH vs Maven).

Why did you pick GH over Maven?

Thank you for taking a look @jmr. It sounded like Maven was a dead end because the credentials were lost and I didn't see any active effort on recovering them. The google team should have access to google packages and could be the fastest way to get the latest release out to consumers. I should have provided that background in the PR; sorry for any confusion there.

If this isn't a great path forward I'm happy to drive the code changes with some guidance on navigating the locked out maven account.

[jmr]

I'll see if I can get the maven access back.

[ThomasThelen]

I'll see if I can get the maven access back.

Not the funnest task to do on a Friday. I appreciate you looking into this @jmr