Migrate manifest to v3 as it will be deprecated soon

[saptarshimondal]

Upgrade manifest to v3 as it will not work on chrome from July, 2023.

Reference - Manifest v2 support timeline

[saptarshimondal]

Manifest v3 still haven't released yet for mozilla firefox. Currently it is supported by google chrome. Waiting till it's release for firefox.
Ref - Manifest version 3 is not supported for Firefox extensions