Adopt `binderhub` #128

Job	Run time
Build tljh_repo2docker	1m 23s
Isolated tests	39s
Integration tests (local)	10m 54s
Unit tests (3.8)	12m 11s
Integration tests (binderhub)	24m 34s
Unit tests (3.9)	16m 29s
Unit tests (3.10)	16m 41s
	1h 22m 51s

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