Fix pydot tests #2232

Job	Run time
No leftovers	3m 1s
build_test_container	9m 45s
CWL conformance (v1.0, docker)	6m 2s
Test on macos-latest	3m 24s
CWL conformance (v1.0, singularity)	6m 30s
cwltool release test	5m 15s
CWL conformance (v1.0, podman)	6m 19s
Tox (3, 8, lint)	1s
Linters (lintreadme)	38s
Tox (3, 8, unit)	1s
CWL conformance (v1.1, docker)	7m 19s
Linters (shellcheck)	12s
Tox (3, 8, bandit)	1s
CWL conformance (v1.1, singularity)	8m 16s
Tox (3, 8, mypy)	1s
Linters (pydocstyle)	19s
CWL conformance (v1.1, podman)	7m 30s
Tox (3, 9, lint)	1s
CWL conformance (v1.2, docker)	8m 55s
Tox (3, 9, unit)	1s
CWL conformance (v1.2, singularity)	9m 39s
Tox (3, 9, bandit)	1s
CWL conformance (v1.2, podman)	9m 2s
Tox (3, 9, mypy)	1s
CWL conformance (v1.2, docker, --fast-parser)	8m 59s
Tox (3, 10, lint)	35s
CWL conformance (v1.3.0-dev1, --relax-path-checks)	5m 32s
Tox (3, 10, unit)	4m 40s
Tox (3, 10, bandit)	27s
Tox (3, 10, mypy)	5m 0s
Tox (3, 11, lint)	30s
Tox (3, 11, unit)	1m 56s
Tox (3, 11, bandit)	30s
Tox (3, 11, mypy)	3m 28s
Tox (3, 12, lint)	29s
Tox (3, 12, unit)	1m 51s
Tox (3, 12, bandit)	30s
Tox (3, 12, mypy)	2m 42s
	2h 9m 23s

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