Bump to v0.24. Updated to support Manifest v3 (MV3).

[richadams]

Google started forcing MV2 extensions to disable, so this extension is going to be broken for most folks until a decision is made for how we proceed here. 😬

This change updates to v0.24 and switches from Manifest v2 (MV2) to Manifest v3 (MV3), which Google now requires for Chrome. The migration guide from Google was followed to make the changes.

The existing Chrome Store listing is managed via my personal Google Developer account, which is... not ideal. What's the best path forward here considering I no longer work for PagerDuty or have merge capability on this repository?

I've had 0.24 staged on the store and ready to go for while, but never made it live as ownership wasn't clear to me (then I forgot all about it, oops). I'm not comfortable updating the store listing to a new version until the changes are reflected in this repo, as this is where existing users expect the source code to be.

I see a few potential paths forward:

1. PagerDuty take ownership of the Chrome Store listing entirely, and then you folks own everything and manage things going forward. This requires reaching out to Google support I believe.
2. PagerDuty merges this change and then I update the existing Chrome Store listing accordingly. Ownership remains a mess, as the repo is owned by PagerDuty, but the store listing is owned by me.
3. Instead of merging this change, update the README to say the tool is no longer maintained by PagerDuty, direct folks to https://github.com/richadams/pagerduty-chrome-notifier as the new source of truth, then archive the repo. I then own and manage things going forward.

I'm fine with any of these options, but feel like (1) is the best path if PagerDuty want to own it, and (3) is the best path overall if PagerDuty no longer wish to have the maintenance burden. Both of those options make ownership clear and reduce confusion. Option (2) just keeps the status quo.

Let me know how you wish to proceed!

[richadams]

I thought of an option (4),

4. PagerDuty republishes the extension with their own Google account, and I remove the existing store listing.

Not a huge fan of that option, since it kinda messes up existing users (they'd need to re-add the extension), but it avoids going through the whole migration process which apparently requires reaching a human at Google to make the change (good luck!), and would get PagerDuty ownership of everything much faster.