use explicit file arguments for additional configs #269

Job	Run time
Tests on paywalled platforms (macos-13-xlarge, 3.12)	1m 47s
Tox test (py38)	3m 38s
Tox test (py39)	3m 35s
Tests on other platforms (windows-2019, 3.10)	4m 47s
Tox test (py310)	3m 39s
Tox test (py311)	3m 22s
Tests on other platforms (windows-2022, 3.11)	4m 5s
Tox test (py312-cover)	6m 37s
Tests on other platforms (windows-2022, 3.12)	4m 16s
Tox test (docs, graphviz)	1m 45s
Tests on other platforms (macos-13, 3.12)	4m 25s
Tests on other platforms (macos-14, 3.12)	1m 58s
Docker image	47s
PyPI packaging	0s
	44m 41s

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