Removed old demo API key to silence GitHub secret scanning warning.

Thanks to xet7 !

packages/wekan-fullcalendar/fullcalendar/demos/gcal.html

@@ -25,7 +25,7 @@
       // THIS KEY WON'T WORK IN PRODUCTION!!!
       // To make your own Google API key, follow the directions here:
       // http://fullcalendar.io/docs/google_calendar/
-      googleCalendarApiKey: 'AIzaSyDcnW6WejpTOCffshGDDb4neIrXVUA1EAE',
+      googleCalendarApiKey: '...',
 
       // US Holidays
       events: 'en.usa#holiday@group.v.calendar.google.com',