changed events should send email

[Zweihorn]

Is your feature request related to a problem? Please describe.

Apparently, changing an event does not send emails to participants about the change and this becomes lost to external clients which accepted the event after the first invitation (e.g., Thunderbird).

Describe the solution you'd like

Changing the date and/or time of an event shall send emails to participants about the change as applicable.

Describe alternatives you've considered

none

Additional context

May be a duplicate but this plethora of issues found with searching "change" made it difficult to find one in due time if this would exist already. 😇

However, keep on the good work and prosper.

🌻