Update renovate.json

See merge request !1789

Resolve "Show announcements in calendar"

Closes #976

See merge request !1772

Resolve "OAuth: Activate upload of icons"

Closes #1215

See merge request !1784

# Conflicts:
#   CHANGELOG.rst

Resolve "Recurrences without rrule_until don't work"

Closes #1255

See merge request !1783

# Conflicts:
#   CHANGELOG.rst

Resolve "Frontend does not respect configured theme"

Closes #1258

See merge request !1781

Fix frontend components imports

Closes #1253

See merge request !1782

Resolve "PersonalEvents with fullDay error in backend"

Closes #1256

See merge request !1777

Update changelog

See merge request !1780

Fix saving CalendarEvents without recurrence

See merge request !1778

Otherwise a CalendarEvent can not be switched to
non-recurring if it previously was recurring.

Update dependency django-colorfield to ^0.13.0

See merge request !1774

Remove unused argument

Closes #1254

See merge request !1773

Add country to AddressInputType

Closes #1257

See merge request !1776

Resolve "Some Datachecks broken due to new registry obejct changes"

Closes #1252

See merge request !1770

Fix changelog format

See merge request !1768

Do release 4.0

See merge request !1767