build

Update ujson, upickle to 4.1.0 #7164

Job	Run time
docker-tests	20m 33s
format-check	6m 40s
build-mdbook	6s
compiler-warnings	2m 23s
scaladoc-check	2m 50s
integration-tests (ubuntu-latest, oopsla19)	20m 32s
unit-tests (ubuntu-latest)	5m 59s
integration-tests (ubuntu-latest, arrays)	22m 42s
unit-tests (macos-latest)	5m 12s
integration-tests (macos-latest, oopsla19)	23m 24s
	1h 50m 21s

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