add note on that master is always the default

A note that default branch name is likely different. A different branch
name would be very confusing to a beginner, especially when the book
asserts that the default is master.

Author: noureddin

book/02-git-basics/sections/recording-changes.asc

@@ -36,6 +36,15 @@ Finally, the command tells you which branch you're on and informs you that it ha
 For now, that branch is always `master`, which is the default; you won't worry about it here.
 <<ch03-git-branching#ch03-git-branching>> will go over branches and references in detail.
 
+[NOTE]
+====
+GitHub changed the default branch name from `master` to `main` in mid-2020, and other Git hosts followed suit.
+So you may find that the default branch name in some newly created repositories is `main` and not `master`.
+In addition, the default branch name can be changed (as you have seen in <<ch01-getting-started#_default_branch>>), so you may see a different name for the default branch.
+
+However, Git itself still uses `master` as the default, so we will use it throughout the book.
+====
+
 Let's say you add a new file to your project, a simple `README` file.
 If the file didn't exist before, and you run `git status`, you see your untracked file like so: