pango: Update to version 1.50.4

pango: Update to version 1.50.4

- Update from 1.50.0 to 1.50.4
- Update of rootfile
- Changelog
   Overview of changes in 1.50.4, 09-02-2022
	* Tweak synthetic space sizes
	* itemize: Try harder to avoid NULL fonts
	* docs: Some additions
	* Pass synthetic slant to harfbuzz
	* Make sloped carets work with uneven scales
	* Fix serialiation on arm
	* Avoid an uninitialized variable warning
	* Reinstate previous behavior of pango_attr_list_splice
	* Deprecated pango_coverage_ref/unref
	* Fix serialization on non-glibc systems
	* Fix allow-breaks handling
   Overview of changes in 1.50.3, 21-12-2021
	* pango-view: Add --serialize-to option for easy bug reporting
	* Revert a transformation change that broke metrics for vertical text
	* Handle fonts without space glyph (such as icon fonts) better
	* Fix some corner cases of line width accounting
	* Fix line height with emulated Small Caps
   Overview of changes in 1.50.2, 16-12-2021
	* Fix a problem with font fallback for Arabic
	* Fix handling of fonts without a space glyph
	* Various documentation improvements
	* Fix build issues
   Overview of changes in 1.50.1, 10-12-2021
	* Fix a crash in tab handling
	* Fix tab positioning without line wrapping
	* Fix an assertion failure found by fuzzing
	* Make underlines work again for broken fonts

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>