Update CHANGES.rst [ci skip]

Author: radarhere

CHANGES.rst

@@ -5,6 +5,15 @@ Changelog (Pillow)
 9.3.0 (unreleased)
 ------------------
 
+- Use rounding in ImageOps contain() and pad() #6522
+  [bibinhashley, radarhere]
+
+- Fixed GIF remapping to palette with duplicate entries #6548
+  [radarhere]
+
+- Allow remap_palette() to return an image with less than 256 palette entries #6543
+  [radarhere]
+
 - Corrected BMP and TGA palette size when saving #6500
   [radarhere]