[libgdata: 2/3] docs: Document rename of master branch to main

[Philip Withnall <pwithnall src gnome org>]

commit b741c223ae203c1c5014e777172cd3466dd59c1b
Author: Philip Withnall <pwithnall endlessos org>
Date:   Mon Jul 12 14:00:59 2021 +0100

    docs: Document rename of master branch to main
    
    Signed-off-by: Philip Withnall <pwithnall endlessos org>

 README.md | 13 +++++++++++++
 1 file changed, 13 insertions(+)
---
diff --git a/README.md b/README.md
index c969b109..7ff4576d 100644
--- a/README.md
+++ b/README.md
@@ -51,6 +51,19 @@ LIBGDATA_DEBUG=3 ./my-program-name &> libgdata.log
 If `LIBGDATA_DISABLE_DEPRECATED` is defined when compiling against libgdata, all
 deprecated API will be removed from included headers.
 
+## Default branch renamed to `main`
+
+The default development branch of libgdata 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
+```
+
 ## Licensing
 
 libgdata is licensed under the LGPL; see COPYING for more details.