Google/Microsoft floating timezones

[mischasigtermans]

✏️ Describe the bug
In some cases you don't want to sync timezones to a calendar. Apple supports the use of floating events, Google and Microsoft don't. For this case, X-WR-TIMEZONE should be set, with the corresponding local timezone (in my case X-WR-TIMEZONE:Europe/Amsterdam).

✅ Expected behavior
Would be nice to have a way to set the timezone on the Calendar.

Calendar::create()
   ->withoutTimezone('Europe/Amsterdam')
    ...

Resulting in

BEGIN:VCALENDAR
VERSION:2.0
PRODID:spatie/icalendar-generator
NAME:Calendar
X-WR-CALNAME:Calendar
X-WR-TIMEZONE:Europe/Amsterdam
BEGIN:VTIMEZONE
...