[gtk/main: 2/2] Mention main in NEWS and README.md

[Matthias Clasen <matthiasc src gnome org>]

commit 50e4ca8593d12b2de76e4d092d34ec7a1655ede8
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Nov 29 17:42:40 2021 -0500

    Mention main in NEWS and README.md

 NEWS      |  5 +++++
 README.md | 14 ++++++++++++++
 2 files changed, 19 insertions(+)
---
diff --git a/NEWS b/NEWS
index 7704dbe329..ea9f7b6ede 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,8 @@
+Overview of Changes
+===================
+
+* Rename git `master` branch to `main`
+
 Overview of Changes in 4.5.0
 ============================
 
diff --git a/README.md b/README.md
index 98f4122b76..d9d18da8f5 100644
--- a/README.md
+++ b/README.md
@@ -116,6 +116,20 @@ docs/reference/gtk/html/gtk-building.html
 
 Or [online](https://docs.gtk.org/gtk4/building.html)
 
+Default branch renamed to `main`
+--------------------------------
+
+The default development branch of GTK has been renamed to `main`.
+To update your local checkout, use:
+```sh
+git checkout master
+git branch -m master main
+git fetch
+git branch --unset-upstream
+git branch -u origin/main
+git symbolic-ref refs/remotes/origin/HEAD refs/remotes/origin/main
+```
+
 How to report bugs
 ------------------