Automate the release process

[sbrudz]

Currently, the process of releasing a new version of the extension to the Chrome Web Store is completely manual and requires a number of different steps. Because of this, there are many opportunities for human error. Finding the credentials to actually do the release has also been a challenge in the past.

The goal of this ticket is to fully automate the release process so that when code is merged to the master branch and the CI build passes, the changes should get automatically deployed to the web store using the Webstore API.

To enable a round of testing before releasing changes to the broader public, configure a workflow that will publish changes in the pre-release branch to the trusted testers channel. Establish an automated release to beta.

Depends on #71

[maniacialexa]

Split this ticket for beta and public release branches

[sbrudz]

Try using this GitHub action: https://github.com/marketplace/actions/chrome-addon-action

[sbrudz]

Work on this feature has been started on the following branch:
https://github.com/defmethodinc/just-not-sorry/tree/automated-publish
We're waiting for the Chrome Web Store to approve the private beta version of the extension. This ticket is blocked until they complete the approval process. Approvals are currently taking much longer than normal because of Covid-19.