This update for xfce4-genmon-plugin fixes the following issues:

- Update to version 4.3.0
  - Update README after switchover to meson
  - autotools-build: Explicitly require glib, gtk3
  - meson-build: Use shared_module()
  - Replace deprecated exo with libxfce4ui 4.21.0
  - build: Automate copyright year management
  - Add meson build
  - autotools-build: Explicitly require libxfce4util
  - Fix libxfce4panel include
  - Translation Updates