[Pkg-rust-maintainers] Bug#1055364: rust-rayon: please update to v1.8.0

[Peter Green]

> Please update to (at least) newer upstream release v1.8.0.
I just looked at this, the new version of rayon requires
a new version of rayon-core, unfortunately when updating
rayon-core I ran into a test failure that looks like it
may indicate an unintentional API break. I'm not
comfortable uploading this until I get feedback
from upstream.