erofs-utils: upgrade 1.8.3 -> 1.8.4

erofs-utils: upgrade 1.8.3 -> 1.8.4

Changelog:
===========
- Fix unusual PAX header handling for tarerofs;
- Fix LIBARCHIVE.xattr decoding;
- Speed up handling of incompressible data;
- Add a '-E^fragdedupe' option to explicitly disable fragment deduplication;
- Fixes around '-Eall-fragments' and '-Ededupe';
- Use external xxhash library if possible.

Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>