updates for upcoming ASDF standard 1.6.0 #950

Job	Run time
sdist_verify	16s
allowed-fail-tests / Load tox environments	7s
docs / Load tox environments	9s
tests / Load tox environments	7s
tests / py312 (ubuntu-latest)	5m 19s
tests / py311 (ubuntu-latest)	3m 28s
tests / py311-online (windows-latest)	5m 30s
tests / py310 (macos-latest)	5m 48s
tests / py310-oldestdeps (ubuntu-latest)	3m 27s
allowed-fail-tests / py311-devdeps (ubuntu-latest)	2m 4s
docs / build_docs-notebooks (ubuntu-latest)	5m 11s
publish	0s
notify	0s
	31m 26s

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