[ANNOUNCE] Libical 3.0.12

[Allen Winter]

Announcing Libical 3.0.12.  This is the 12th bugfix release for Libical 3.0
This release is binary and source compatible with version 3.0.0.

Highlights of this Release:
-----------------------------------
 * Fix a libicalval crash in cleanVObject
 * METHOD:DECLINECOUNTER must have DTEND or DURATION
 * Handle if DTEND and DURATION are both missing
 * Improved FindICU (copied from official CMake.  see files in cmake/Kitware)
 * Buildsystem fixes (especially for the Ninja generator)
 * Built-in timezones updated to tzdata2021e

The source code can be found on GitHub at: https://github.com/libical/libical

Tarballs and zipballs for v3.0.12 are available from: https://github.com/libical/libical/releases

"Libical is an Open Source implementation of the iCalendar protocols and protocol data units.
The iCalendar specification describes how calendar clients can communicate with calendar
servers so users can store their calendar data and arrange meetings with other users."

Libical implements:
* RFC5545, RFC5546, RFC7529
 * the CalDav scheduling extensions in RFC6638
 * iCalendar extensions in RFC7986
 * plus the iCalendar iMIP protocol in RFC6047.

 For more information about Libical, please visit http://libical.github.io/libical/