.getOccurences finds wrong results when crosses dst mark

[Reeywhaar]

Library relies on minute offsets rather than timezones thus fails to get correct results when timezone offset changes midway (DST crossing)

const event = new CalendarEvent({
  //... weekly from 8 to 17 in America/New_York timezone
})

const occurences = event.occurencesBetween(
    moment('2023-10-20T00:00:00').tz('America/New_York', true),
    moment('2023-11-20T00:00:00').tz('America/New_York', true)
)

expect(occurences.map(([start, end]) => [moment(start).tz('America/New_York').format(), moment(end).tz('America/New_York').format()].join(' '))).toEqual([
  '2023-10-22T09:00:00-04:00 2023-10-22T17:00:00-04:00',
  '2023-10-29T09:00:00-04:00 2023-10-29T17:00:00-04:00',
  '2023-11-05T09:00:00-05:00 2023-11-05T17:00:00-05:00',
  '2023-11-12T09:00:00-05:00 2023-11-12T17:00:00-05:00',
  '2023-11-19T09:00:00-05:00 2023-11-19T17:00:00-05:00',
])

/*
Actual:
Array [
  "2023-10-22T09:00:00-04:00 2023-10-22T17:00:00-04:00",
  "2023-10-29T09:00:00-04:00 2023-10-29T17:00:00-04:00",
  "2023-11-05T08:00:00-05:00 2023-11-05T16:00:00-05:00",
  "2023-11-12T08:00:00-05:00 2023-11-12T16:00:00-05:00",
  "2023-11-19T08:00:00-05:00 2023-11-19T16:00:00-05:00",
]
*/