Re-introduce crossbeam channels

[sharkdp]

After doing a proper performance evaluation, it would be benefitial to use crossbeam channels instead of the std mpsc channels, because:

• there are some issues with the std channels version of recv_timeout() (Panic in Receiver::recv() rust-lang/rust#39364)
• the current channels are not size-restricted and can lead to large memory usage
• crossbeam channels are "supposed to be" faster.

See discussion in #895 and #916.

[tavianator]

Looks like Rust might do this for us :) rust-lang/rust#93563

[ijoseph]

fwiw, removing the second -u

i.e. from

fd -uu  --glob -p  '**/src/kustomization.yaml'

to

fd -u  --glob -p  '**/src/kustomization.yaml'

was a valid workaround in my case

[tavianator]

@ijoseph Makes sense, but that won't work any more after #986. You'll have to do fd -I explicitly.