Tor Browser nightly builds include an old https-everywhere version

In projects/https-everywhere/config we are using the master branch for nightly builds, from the git repository https://git.torproject.org/https-everywhere.git

However the master branch on this repository is currently 12 months old.

To fix that, I think we could either:

• use the master branch from https://github.com/EFForg/https-everywhere instead of https://git.torproject.org/https-everywhere.git, which seems to be updated frequently
• ask legind to update the master branch on https://git.torproject.org/https-everywhere.git more frequently
• not use the master branch in nightly builds but instead use the same tag as in the alpha. We can also update this tag manually when a new https-everywhere version is released, even when we don't plan to release a new Tor Browser soon, to include it in the nightly.