singularity: improve testing on version 4.x+ #2451

Job	Run time
No leftovers	3m 20s
build_test_container	10m 22s
CWL conformance (v1.0, docker)	6m 32s
CWL conformance (v1.0, singularity)	6m 38s
Test on macos-latest	5m 53s
CWL conformance (v1.0, podman)	7m 0s
cwltool release test	13m 38s
Tox (3, 9, lint)	28s
CWL conformance (v1.1, docker)	7m 46s
Tox (3, 9, unit)	5m 9s
CWL conformance (v1.1, singularity)	7m 37s
Linters (lintreadme)	29s
Tox (3, 9, bandit)	23s
CWL conformance (v1.1, podman)	7m 49s
Linters (shellcheck)	15s
Tox (3, 9, mypy)	7m 3s
CWL conformance (v1.2, docker)	9m 34s
Linters (pydocstyle)	24s
Tox (3, 10, lint)	36s
CWL conformance (v1.2, singularity)	9m 34s
Tox (3, 10, unit)	4m 56s
CWL conformance (v1.2, podman)	9m 25s
CWL conformance (v1.2, docker, --fast-parser)	9m 27s
Tox (3, 10, bandit)	37s
CWL conformance (v1.3.0-dev1, --relax-path-checks)	6m 9s
Tox (3, 10, mypy)	7m 1s
Tox (3, 11, lint)	26s
Tox (3, 11, unit)	4m 45s
Tox (3, 11, bandit)	22s
Tox (3, 11, mypy)	6m 18s
Tox (3, 12, lint)	31s
Tox (3, 12, unit)	6m 19s
Tox (3, 12, bandit)	31s
Tox (3, 12, mypy)	7m 16s
Tox (3, 13, lint)	38s
Tox (3, 13, unit)	6m 48s
Tox (3, 13, bandit)	32s
Tox (3, 13, mypy)	1m 8s
	3h 3m 39s

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