Update extension manifest from v2 to v3

[escapedcat]

Is your feature request related to a problem?

Update extension to new manifest version to make sure it will not be an issue to be listed in Chrome the extension store in the future.

Describe the solution you'd like

Extension ships with v3 manifest

Describe alternatives you've considered

none

Additional context

They've also put out a new spec that extensions need to conform to (Manifest v3)

Add any other additional context or screenshots about the feature request here

• https://developer.chrome.com/blog/mv2-transition/
• https://developer.chrome.com/docs/extensions/mv3/mv3-migration-checklist/
• https://developer.chrome.com/docs/extensions/mv3/intro/mv3-migration/
• wasm does not work in v3 (? - as of Juni 2022):
  • https://bugs.chromium.org/p/chromium/issues/detail?id=1173354
  • https://bugs.chromium.org/p/chromium/issues/detail?id=1318922
• https://github.com/GoogleChrome/chrome-extensions-samples/tree/main/examples

Are you working on this?

Partly, see related PR