glib: Update to 2.68.2

glib: Update to 2.68.2

- Update from 2.68.1 to 2.68.2
- Update rootfiles
- Changelog
   Overview of changes in GLib 2.68.2
    * Fix building third-party projects against GLib on CentOS 7 (work by
      Ignacio Casal Quinteiro) (#2387)
    * Bugs fixed:
      - #2387 json-glib does not build with glib 2.68.1
      - !2060 gmacros: check that __cplusplus or _MSC_VER is defined
      - !2068 gmacros: missing check if __STDC_VERSION__ is defined
      - !2079 Backport !2078 “gthreadedresolver: don't ignore flags in lookup_by_name_with_flags” to glib-2-68
    * Translation updates:
      - Nepali
      - Serbian

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