Create LICENSE.txt
Create LICENSE.txt

Copied verbatim from the receipts repo https://github.com/excid3/receipts/blob/master/LICENSE.txt
timshingyu/simple_calendar,sdbeng/simple_calendar,excid3/simple_calendar,rodrigoargumedo/simple_calendar,rodrigoargumedo/simple_calendar,excid3/simple_calendar,rodrigoargumedo/simple_calendar,sdbeng/simple_calendar,TuxmAL/simple_calendar,excid3/simple_calendar,timshingyu/simple_calendar,timshingyu/simple_calendar,TuxmAL/simple_calendar,sdbeng/simple_calendar