Chrome MV3 Beta channel

[sammacbeth]

Reviewer:

Description:

https://app.asana.com/0/0/1203197597853167/f

• Set up build process for a Chrome MV3 beta build.
• Add an action that we can trigger to automatically publish a new version to the Chrome beta channel.

Steps to test this PR:

Automated tests:

• Unit tests
• Integration tests

Reviewer Checklist:

• Ensure the PR solves the problem
• Review every line of code
• Ensure the PR does no harm by testing the changes thoroughly
• Get help if you're uncomfortable with any of the above!
• Determine if there are any quick wins that improve the implementation

PR Author Checklist:

• Get advice or leverage existing code
• Agree on technical approach with reviewer (if the changes are nuanced)
• Ensure that there is a testing strategy (and documented non-automated tests)
• Ensure there is a documented monitoring strategy (if necessary)
• Consider systems implications

[GioSensation]

I haven't tested it, but it looks great. I've just left a couple of comments related to new action versions that I was forced to use in recent tests. Not sure if it applies here, but it's probably worth upgrading anyway. Up to you.

Also, please check the integration test failure. Not sure if it's related.