Bump icalendar from 5.0.13 to 6.0.0

Bumps [icalendar](https://github.com/collective/icalendar) from 5.0.13 to 6.0.0.
- [Release notes](https://github.com/collective/icalendar/releases)
- [Changelog](https://github.com/collective/icalendar/blob/main/CHANGES.rst)
- [Commits](collective/icalendar@v5.0.13...v6.0.0)

---
updated-dependencies:
- dependency-name: icalendar
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

requirements.txt

@@ -23,7 +23,7 @@ drf-spectacular[sidecar]==0.27.2
 easy-thumbnails==2.10
 flower==2.0.1
 fontawesomefree~=6.6.0
-icalendar==5.0.13
+icalendar==6.0.0
 invoke==2.2.0
 openfoodfacts==1.1.3
 pillow==10.4.0