Make manifest V3 the new default setup

[Danscap]

Manifest V2 is being phased out

As many of you are aware, Google is doing away with manifest V2. Whether most of us disagree with their decision is irrelevant, and they have already stated that in 2023 manifest V2 extensions will not be allowed into the Chrome Web Store, or work in the Chrome browser.

I propose making the changes to the manifest.json file, and any other files that need to updated, the standard when creating a new project with this tool.

Relevant Issues: https://github.com/VasilyShelkov/create-react-extension/issues/36