Bump caldav from 1.6.0 to 2.0.0 (#3562)

Bumps [caldav](https://github.com/python-caldav/caldav) from 1.6.0 to 2.0.0.
- [Release notes](https://github.com/python-caldav/caldav/releases)
- [Changelog](https://github.com/python-caldav/caldav/blob/master/CHANGELOG.md)
- [Commits](https://github.com/python-caldav/caldav/compare/v1.6.0...v2.0.0)

---
updated-dependencies:
- dependency-name: caldav
  dependency-version: 2.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

pyproject.toml

@@ -76,7 +76,7 @@ dependencies = [
         # User
         "drf-nested-routers",
         "vobject",
-        "caldav==1.6.0"
+        "caldav==2.0.0"
 ]
 [project.optional-dependencies]
 dev = [