Add test or steep check by rake task in README #1092

Job	Run time
test-memory (head)	25s
steep-check (head)	11s
test-ruby (head, master)	5m 11s
check-misc (head)	7s
test-ruby (3.0, master)	5m 23s
test-windows (head)	2m 16s
test-ruby (2.7, master)	5m 26s
ruby-versions / Generate Ruby versions	1s
test (2.5)	22s
test (2.6)	23s
test (2.7)	22s
test (3.0)	12s
test (3.1)	8s
test (3.2)	12s
test (3.3)	10s
test (head)	10s
	20m 59s

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