Add Windows changes

Author: smplayer-dev

Release_notes.md

@@ -10,8 +10,12 @@
  * Some bug fixes.
 ### Linux
  * Ignore KDE's "single click". It causes unexpected behaviour.
+### Windows
+ * It's easier to update the YouTube code.
+ * The installer is digitally signed.
+ * SMPlayer is now also available in the Windows Store.
 ### Mac OS
- * Fix playback with mplayer when screenshots were enabled.
+ * Fix playback with mplayer when screenshots are enabled.
 ### Removed
  * Support for the obsolete mplayer2.