libplist: Update to version 2.3.0

libplist: Update to version 2.3.0

- Update from version 2.2.0 to 2.3.0
- Update of rootfile
    2.3.0
	- Changes:
	  * Rename PLIST_UINT to PLIST_INT and add plist_new_int() and plist_get_int_val()
	  * Add support for JSON format
	  * Add support for OpenStep format
	  * Introduce error codes and format constants
	  * Add return value to import/export functions to allow returning error codes
	  * Add new plist_sort function
	  * Add several human-readable output-only formats
	  * Add new plist_write_to_string/_stream/_file functions
	  * Add new plist_print function
	  * Add new plist_read_from_file function
	  * Add new plist_mem_free() function
	  * Add a few C++ methods
	  * Add C++ interface test
	  * Add PLIST_NULL type
	  * Some code housekeeping (mostly clang-tidy)
	- Breaking:
	  * plist_from_memory() gets additional parameter
	- Bugfixes:
	  * Fix multiple bugs in all of the parsers
	  * Fix handling of PLIST_UID nodes

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