expat: Update to version 2.6.2

expat: Update to version 2.6.2

- Update from version 2.6.1 to 2.6.2
- Update of rootfile
- Changelog
    2.6.2
       Security fixes:
       #839 #842  CVE-2024-28757 -- Prevent billion laughs attacks with
                    isolated use of external parsers.  Please see the commit
                    message of commit 1d50b80cf31de87750103656f6eb693746854aa8
                    for details.
       Bug fixes:
       #839 #841  Reject direct parameter entity recursion
                    and avoid the related undefined behavior
       Other changes:
            #847  Autotools: Fix build for DOCBOOK_TO_MAN containing spaces
            #837  Add missing #821 and #824 to 2.6.1 change log
       #838 #843  Version info bumped from 10:1:9 (libexpat*.so.1.9.1)
                    to 10:2:9 (libexpat*.so.1.9.2); see https://verbump.de/
                    for what these numbers do

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