finally got it working with

		 {
				module: "calendar",
				header: "Abfallkalender",
				position: "top_left",
				config:
					{
						calendars: [
							{
									url: "https://calendar.google.com/calendar/ical/...group.calendar.google.com/private-.../basic.ics",
	                                maximumNumberOfDays: 14,
	                            	maximumEntries: 5,
							},
						],
					},
		},