Fixed manifest for Firefox, added linting and CI

[mjasikowski]

Fixed problems with the FF extension by using the web-ext package from Mozilla, which helps with linting.
Web-ext linting was also added as a step to GitHub actions, so we can be sure it's compatible with Firefox without having to first package and upload to addons.mozilla.org.

[mjasikowski]

Not sure while snyk licensing is failing (the only package added was web-ext which has MPL 2.0) - I don't have access to Expensify's Snyk org.

[francoisl]

I sent you an invite to Snyk. In the meantime, we can manually mark the check as succsesful in Snyk, which I just did.

The merge-base changed after approval.

The merge-base changed after approval.

[tgolen]

Trying to approve again.

The merge-base changed after approval.

[tgolen]

Still getting auto-rejected :(

The merge-base changed after approval.

[dangrous]

dang, thought i'd be lucky haha

[mjasikowski]

Waiting for GitHub to get back to me on the support ticket

[mjasikowski]

@dangrous @tgolen it's fixed now, closing and reopening PRs works

[dangrous]

wooo

[tgolen]

Yay, that worked. I'm publishing it now and then you can send out an email to everyone announcing the new version once I give you the green light.

[tgolen]

OK, green light! I've uploaded it to 1Password.

Send an email to @ALL to let anyone know they can update by following the steps from I use firefox, how do I install the Kernel Scheduler (KS) browser extension?

[tgolen]

Here is an example email I sent out a while ago:

[mjasikowski]

@tgolen I'll go through the remaining snyk PRs, bump the version number and then deal with the e-mail - at least we'll have a "security updates" changelog entry for that