GitHub protected branches are now enabled

[Vladimir Panteleev via Digitalmars-d]

Hi all,

As an experiment, we've enabled some new GitHub branch protection 
features for the Phobos, Tools and dlang.org repos:

1. The auto-tester and the documentation tester must be green 
before a PR can be merged. As PRs should be merged via the 
auto-tester's Auto Merge feature, and the doc tester finishes 
much quicker than the autotester, I don't expect this to affect 
procedure much.

2. Before a PR can be merged, it must now have one "approved" 
review. So, it's a good time to start using GitHub's new review 
features instead of "LGTM" comments :)

3. Enabling CI protection has the added bonus that pushing 
directly to the branch is disabled. This means you don't need to 
worry about accidentally pushing to the wrong git remote.

4. Admins can bypass these restrictions. If these are preventing 
you from getting things done, ping an admin.

If things go well, we'll enable the checks for the Druntime and 
DMD repositories as well.

Feedback is welcome!