Support of subscription calendars

[HadrienKulik]

Excellent job on this script!

We would love to see it supporting subscribing to a calendar (the feature where you can subscribe to an external dynamic .ics, for instance to load and always sync all the days off in your country with your calendar)

Addevent.com has a specific button for that: https://www.addevent.com/documentation/add-to-calendar-button-for-calendars and I have never found a good open source alternative! 😔