Adjust CI for antsibull-core v3 #947

Job	Run time
Build stable docsite	3m 50s
Build devel docsite	5m 1s
Build simple docsite (extra options: --use-current --sphinx-theme sphinx_rtd_theme)	3m 5s
Build simple docsite (extra options: --use-current --sphinx-theme sphinx_rtd_theme)	3m 13s
Build simple docsite (extra options: --no-indexes --squash-hierarchy --intersphinx ansible7:https://docs.ansible.com/ansible/6/ community.crypto --collection-version 2.0.0)	1m 10s
Build simple docsite (extra options: --no-indexes --squash-hierarchy --intersphinx ansible7:https://docs.ansible.com/ansible/6/ community.crypto --collection-version 2.0.0)	1m 3s
Build simple docsite (extra options: --use-current --use-html-blobs --no-breadcrumbs community.crypto community.docker)	1m 30s
Build simple docsite (extra options: --use-current --output-format simplified-rst community.crypto community.docker)	1m 52s
	20m 44s

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