Missing support for zstd compression

[mrg358]

Please consider adding support for zstd compression.

appimage-cli-tool install https://github.com/simplex-chat/simplex-chat/releases/download/v5.4.2/simplex-desktop-x86_64.AppImage
Downloading 100% |████████████████████████████████████████████████████████████████████████████████████████████████████████| (238/238 MB, 18.165 MB/s) [13s:0s]
Creating menu entry and mime-types integrations
Squashfs image uses zstd compression, this version supports only lzo, xz, zlib, lz4.
ERROR: appimage_register_in_system : sqfs_open_image error: /home/ubuntu/Applications/simplex-desktop-x86_64.AppImage
Integration failed: unregister failed