[ANNOUNCE] Libical 3.0.9

[Allen Winter]

Announcing Libical 3.0.9.  This is the 9th bugfix release for Libical 3.0

Highlights of this Release:
-----------------------------------
 * Add support for empty parameters, e.g. CN=""
 * Accept VTIMEZONE with more than one X- property
 * Several fixes for recurrences containing BYWEEKNO
 * icalrecurrencetype_from_string() will reject any RRULE that contains a rule-part that occurs more than once
 * Improve thread safety
 * Fix compiled-in path for the built-in timezone data
 * Fix reading TZif files with empty v1 data (use v2+ whenever possible)
 * Add backwards compatibility for previous TZIDs
 * Built-in timezones updated to tzdata2020d
 * Fix build with newer libicu
 * Fix cross-compile support in libical-glib

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

Tarballs and zipballs for v3.0.9 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/