Needed for GNOME Appdata

- Update to version version 2.11.2:
+ added support for `-o -`.
+ windows/JNI build fixes.
- Changes from version 2.8:
+ libimagequant is a separate project.
+ --strip option to disable copying of PNG metadata.
- Changes from version 2.7:
+ improved dithering of saturated and semitransparent colors.
+ fixed order of log output when using openmp.
+ improved quality sanity check in --skip-if-larger option.
+ disabled palette post-processing on colors from --map option to
preserve them exactly.
- Changes from version 2.6:
+ when source image has no color profile information, the output
won't have either.
- Changes from version 2.5:
+ replaced color search algorithm with vantage point tree, which
is much faster and more reliable.
+ deprecated IE6 workaround.
+ warn when compiled without color profile support.
+ Rust API for libimagequant.
- Changes from version 2.4:
+ fixed remapping of bright colors when dithering.
- BuildRequire libimagequant-devel: the library lives in a separate
project since version 2.8.
- update to version 2.3.1
- Update to version 2.3.0
- Building with OpenMP support makes pngquant faster in wall-clock time on multicore machines when one image at a time is processed.
- Version 1.8.0