[Common Voice] web part: name changes in domain and repo

[Peiying Mo]

Hello Localizers,

There are a few changes in Common Voice that I would like to share. It
shouldn't impact what you have been doing in Pontoon.

`Voice` is now changed to `commonvoice`:

- *Dev server*: https://dev.commonvoice.allizom.org/ - working on
getting the team to update this site once a day so you can test your
localization work
- *Staging server*: https://commonvoice.allizom.org/ - updated a few
days before production push, working with the team to get a predictable
date.
- *Production server*: http://commonvoice.mozilla.org - updated once
every other Tuesday.

The *repo* is also renamed from `master` to `main` in addition to the
domain name change:

- Web part repo:
https://github.com/mozilla/common-voice/tree/main/web/locales
- To report issues: https://github.com/mozilla/common-voice/issues

Thank you,
Peiying