makepkg: add new checksum algorithm via b3sum
BLAKE3 is a modern and fast hash function: https://github.com/BLAKE3-team/BLAKE3
The main advantage is when checking integrity of very large files (Firefox, Chromium come to mind). It is not a silver bullet though, as B3.asc files are usually not distributed as SHA256.asc are.
Unscientific benchmark:
% hyperfine --prepare='sleep 60' 'updpkgsums' # for chromium
Time (mean ± σ): 3.545 s ± 0.696 s [User: 1.842 s, System: 0.751 s] (sha256sums)
Time (mean ± σ): 679.5 ms ± 131.1 ms [User: 1678.6 ms, System: 357.0 ms] (b3sums)
b3sum is not built into coreutils, but is available as CC0 or Apache-licensed code.
This commit was directly inspired by e03752e6
Edited by Moviuro