Use relative times for calendar events in protocol 7 documentation

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Fixes #323!
Related to #316.

This PR replaces the fixed times for calendar events with relative times for tomorrow in the protocol 7 documentation. This fixes a documentation bug where Time.now in the complete code example advances past the fixed calendar event times.

From #323:

Related to #316.
Related to #321.

The DSI e-BRAIN (protocol 7) uses 5 minute intervals relative to the current date of the device time as the event time. This means that if the device time is midnight, and the event if at 00:15, the calendar event time is sent as "3". If the event is midnight on the next day, it is sent as "288" (1440 minutes in a day / 5 minutes).

Since this is relative to the device time, if a calendar event happens to be before the device time, then the calendar event time will have a negative value due to it being relative to the device time. With #322, calendar event times are now validated, and a event before the device time will raise a message like so:

Validation failed: Time 2022-12-13 09:00:00 -0800 must be greater or equal to device time! (ActiveModel::ValidationError)

The protocol 7 documentation includes a combination of Time.now for the device time, and two times in December, 2022 as calendar event times:

timex_datalink_client/docs/dsi_ebrain_protocol_7.md

Lines 220 to 239 in ae4cdb4

	time = Time.now
	breakfast_with_cousins = phrase_builder.vocab_ids_for("Breakfast", "With", "Cousins")
	crashing_around_the_house = phrase_builder.vocab_ids_for("Crashing", "Around", "The", "House")
	events = [
	TimexDatalinkClient::Protocol7::Eeprom::Calendar::Event.new(
	time: Time.new(2022, 12, 13, 9, 0, 0),
	phrase: breakfast_with_cousins
	),
	TimexDatalinkClient::Protocol7::Eeprom::Calendar::Event.new(
	time: Time.new(2022, 12, 13, 19, 0, 0),
	phrase: crashing_around_the_house
	)
	]
	calendar = TimexDatalinkClient::Protocol7::Eeprom::Calendar.new(
	time: time,
	events: events
	)

While the protocol 7 documentation worked well when it was written, time has passed, and the 2022 dates are now before Time.now, so the complete code example in the protocol 7 documentation now raises exceptions when used.

This should be fixed so that the example works at any point in time. Since the calendar event times are relative to the device time, and the example uses a relative Time.now device time, the failure-proof way to fix this documentation would be to make the event examples relative to Time.now, too.