Fix "What's new" URL to direct to latest version

Summary

Summarize the bug encountered concisely. Currently the "What's new" URL goes to https://www.torproject.org/releases/ which doesn't have the 13.0 release on it. It should instead go to https://blog.torproject.org/new-release-tor-browser-130/ for the 13.0 release, and programitcally go to the {current version} blog post.

Steps to reproduce:

How one can reproduce the issue - this is very important.

1. Make a new tab
2. Go to quick settings
3. Tap on "What's new", notice that you go to https://www.torproject.org/releases/ which only goes up to 12.0

Environment

Which operating system are you using? For example: Debian GNU/Linux 10.1, Windows 10, Ubuntu Xenial, FreeBSD 12.2, etc. Which installation method did you use? Distribution package (apt, pkg, homebrew), from source tarball, from Git, etc.

Relevant logs and/or screenshots