pango: Update to version 1.50.6

pango: Update to version 1.50.6

- Update from 1.50.4 to 1.50.6
- Update of rootfile
- Changelog
    Overview of changes in 1.50.6, 19-03-2022
	- Drop hb-glib dependency
	- Fix test font configuration
	- Maintain order in pango_attr_list_change
	- Fix a use-after-free in pango_attr_list_change
    Overview of changes in 1.50.5, 03-03-2022
	* Fix compiler warnings
	* Enable cairo by default
	* pango-view: Show more baselines
	* layout: Handle baselines
	* Windows: build cleanups

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>