Log Message:
gexiv2: Update to 0.12.1

gexiv2 0.12.1 - 23 May 2020

 * Support macOS dylib versioning
 * Improve compatibility with current exiv2 development versions
 * Fix compiling on windows
 * Fix issue with problematic symbol visibility of exiv2
 * Fix issues with tests overwriting environment variables
 * Fix exception escaping on division by zero
 * Fix overflow in altitude fraction conversion
 * Fix crash with experimental GIO support
 * Documentation fixes
 * Add gexiv2_metadata_update_gps_info which will not remove all other GPS
   information

Bugs fixed in this release:
 - https://gitlab.gnome.org/GNOME/gexiv2/issues/41
 - https://gitlab.gnome.org/GNOME/gexiv2/issues/42
 - https://gitlab.gnome.org/GNOME/gexiv2/issues/45
 - https://gitlab.gnome.org/GNOME/gexiv2/issues/52
 - https://gitlab.gnome.org/GNOME/gexiv2/issues/53
 - https://gitlab.gnome.org/GNOME/gexiv2/issues/54
 - https://gitlab.gnome.org/GNOME/gexiv2/issues/55