CHANGELOG: Add changelog entry for ignoring MIDI Beat Clock messages

Author: Holzhaus

CHANGELOG

@@ -17,6 +17,7 @@
 * Add controller mapping for Stanton DJC.4 #2607
 * Fix broadcasting via broadcast/recording input lp:1876222 #2743
 * Only apply ducking gain in manual ducking mode when talkover is enabed lp:1394968 lp:1737113 lp:1662536 #2759
+* Ignore MIDI Clock Messages (0xF8) because they are not usable in Mixxx and inhibited the screensaver #2786
 
 ==== 2.2.3 2019-11-24 ====