Added release notes

Author: radarhere

docs/releasenotes/12.1.0.rst

@@ -41,6 +41,16 @@ TODO
 API additions
 =============
 
+Added ``scale_down`` argument to ``ImageGrab.grab()``
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+:py:meth:`~PIL.ImageGrab.grab` now accepts an optional keyword argument of
+``scale_down``. This affects macOS screenshots with a ``bbox`` on a Retina screen. By
+default, images will be captured at 2x. If ``scale_down`` is ``True``, they will be at
+1x.
+
+Previously, macOS screenshots with a ``bbox`` were captured at 1x by default.
+
 Specify window in ImageGrab on macOS
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^