Expand Zip to up to 9 producers #566

Job	Run time
docs/nightly	22s
format/nightly	16s
cargo-careful	1m 21s
miri	10m 58s
nostd/thumbv6m-none-eabi/stable	20s
cross_test/s390x-unknown-linux-gnu/stable	1m 2s
Pass MSRV values to other jobs	3s
cross_test/i686-unknown-linux-gnu/stable	53s
clippy/stable	24s
tests/beta	1m 15s
blas-msrv	42s
tests/nightly	1m 12s
tests/1.64.0	1m 25s
tests/stable	1m 20s
conclusion	-1s
	21m 32s

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