rust: upgrade minimum `rayon` dependency
The 1.6.0 and 1.6.1 releases fixes a soundness issue and a performance issue
that are both important to us, since both correctness and performance are
paramount in the Rust extensions.
fixbundle() {
grep -v 'saving bundle' | grep -v 'saved backup' | \
grep -v added | grep -v adding | \
grep -v "unable to find 'e' for patching" | \
grep -v "e: No such file or directory" | \
cat
}