ANNOUNCE: xfconf 4.21.0 released

[Gaël Bonithon]

xfconf 4.21.0 is now available for download from
  
  https://archive.xfce.org/src/xfce/xfconf/4.21/xfconf-4.21.0.tar.xz
  https://archive.xfce.org/src/xfce/xfconf/4.21/xfconf-4.21.0.tar.xz?sha1
  https://archive.xfce.org/src/xfce/xfconf/4.21/xfconf-4.21.0.tar.xz?sha256


What is xfconf?
===============

Xfconf is a flexible, easy-to-use configuration management system.

Website: 
  https://docs.xfce.org/xfce/xfconf/start


Release notes for 4.21.0
========================
[Please note that this is a development release.]

- build: Automate copyright year management
- meson-build: Add missing function checks
- meson-build: Use SPDX license expression
- meson-build: Add tests option
- meson-build: Use 'pkgconfig_define' in dep.get_variable()
- meson-build: Use 'dependencies' in cc.alignment()
- meson-build: Update debug/optimization flag management
- meson-build: Add missing gir prefixes
- meson-build: Use path builder and fs instead of literal '/'
- Add meson build
- tests: Always cleanup xfconfd process
- tests: Enable t-list-channels test
- tests: Fix test failure because of xfconfd not running
- Migrate to xdt-gen-visibility and xdt-check-abi
- channel: Complete and harmonize docs of
get_string_list()/get_arrayv()
- channel: Warn in case of failure in get_string_list()
- channel: Fix get_arrayv() return value
- Translation Updates:
  Albanian, Slovak