revert to schema-salad 8.4.20230817074451 to fix format field handling #719

Job	Run time
cwl-utils release test	3m 58s
CI tests via Tox (3, 8, lint)	37s
CI tests via Tox (3, 8, unit)	2m 48s
CI tests via Tox (3, 8, bandit)	39s
CI tests via Tox (3, 8, mypy)	35s
CI tests via Tox (3, 9, lint)	30s
CI linters via Tox (lint-readme)	25s
CI tests via Tox (3, 9, unit)	1m 23s
CI linters via Tox (pydocstyle)	23s
CI tests via Tox (3, 9, bandit)	44s
CI tests via Tox (3, 9, mypy)	38s
CI tests via Tox (3, 10, lint)	24s
CI tests via Tox (3, 10, unit)	3m 9s
CI tests via Tox (3, 10, bandit)	33s
CI tests via Tox (3, 10, mypy)	52s
CI tests via Tox (3, 11, lint)	21s
CI tests via Tox (3, 11, unit)	1m 27s
CI tests via Tox (3, 11, bandit)	26s
CI tests via Tox (3, 11, mypy)	1m 14s
CI tests via Tox (3, 12, lint)	29s
CI tests via Tox (3, 12, unit)	2m 52s
CI tests via Tox (3, 12, bandit)	28s
CI tests via Tox (3, 12, mypy)	39s
	25m 34s

Provide feedback