Switch main branch to `main`

[lgarron]

@engedy, would you be up for changing the default branch at https://github.com/chromium/permission.site/settings to main?

I think this should automatically update the branch used by https://github.com/chromium/permission.site/settings/pages but that would also be good to check.

(I don't have access to the settings myself, neither to edit nor to check.)

[ShivaKoushik33]

Hi 👋, I’d love to contribute to this!
Should I go ahead and prepare a PR to update master references to main in the docs/configs?

[lgarron]

Should I go ahead and prepare a PR to update master references to main in the docs/configs?

Appreciate the enthusiasm, but that won't be necessary.