Pontoon: Update Vietnamese (vi) localization of Thimble
Pontoon: Update Vietnamese (vi) localization of Thimble

Localization authors:
- Đặng Duy Thanh <thanhdd.it@gmail.com>

mozilla/thimble.mozilla.org,mozilla/thimble.mozilla.org,humphd/thimble.mozilla.org,humphd/thimble.mozilla.org,mozilla/thimble.mozilla.org,mozilla/thimble.mozilla.org,humphd/thimble.mozilla.org,humphd/thimble.mozilla.org