Update black requirement to allow for newer versions #915

Job	Run time
cwl-utils release test	3m 38s
CI linters via Tox (lint-readme)	23s
CI linters via Tox (pydocstyle)	18s
CI tests via Tox (3, 9, lint)	15s
CI tests via Tox (3, 9, unit)	2m 19s
CI tests via Tox (3, 9, bandit)	28s
CI tests via Tox (3, 9, mypy)	49s
CI tests via Tox (3, 10, lint)	20s
CI tests via Tox (3, 10, unit)	1m 59s
CI tests via Tox (3, 10, bandit)	23s
CI tests via Tox (3, 10, mypy)	45s
CI tests via Tox (3, 11, lint)	24s
CI tests via Tox (3, 11, unit)	2m 23s
CI tests via Tox (3, 11, bandit)	23s
CI tests via Tox (3, 11, mypy)	54s
CI tests via Tox (3, 12, lint)	14s
CI tests via Tox (3, 12, unit)	2m 6s
CI tests via Tox (3, 12, bandit)	26s
CI tests via Tox (3, 12, mypy)	48s
CI tests via Tox (3, 13, lint)	23s
CI tests via Tox (3, 13, unit)	2m 21s
CI tests via Tox (3, 13, bandit)	32s
CI tests via Tox (3, 13, mypy)	1m 29s
	24m 0s

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