Bump icalendar from 2.5.2 to 2.5.3
Bump icalendar from 2.5.2 to 2.5.3

Bumps [icalendar](https://github.com/icalendar/icalendar) from 2.5.2 to 2.5.3.
- [Release notes](https://github.com/icalendar/icalendar/releases)
- [Changelog](https://github.com/icalendar/icalendar/blob/master/History.txt)
- [Commits](https://github.com/icalendar/icalendar/compare/v2.5.2...v2.5.3)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
sue445/rubicure_api,sue445/rubicure_api,sue445/rubicure_api