Add missing required param to README #1460

Job	Run time
Rust nightly on Linux	15s
Rust beta on Linux	14s
Rust stable on Linux	8s
Rust 1.62.0 on Linux	13s
Rust stable 18 months ago on Linux	10s
Rust stable minus 8 releases on Linux	15s
Rust nightly on macOS	38s
Rust beta on macOS	44s
Rust stable on macOS	48s
Rust 1.62.0 on macOS	28s
Rust stable 18 months ago on macOS	20s
Rust stable minus 8 releases on macOS	22s
Rust nightly on Windows	31s
Rust beta on Windows	35s
Rust stable on Windows	1m 41s
Rust 1.62.0 on Windows	21s
Rust stable 18 months ago on Windows	23s
Rust stable minus 8 releases on Windows	43s
Rust 1.0.0 on Linux	10s
	8m 59s

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