Update coursier to 2.1.6 #1839

Job	Run time
conformance	2m 37s
build (2_12, mima)	1m 37s
build (2_12, e2e)	4m 59s
build (2_12, proptest)	11m 44s
build (2_13, mima)	1m 26s
build (2_13, e2e)	5m 10s
build (2_13, proptest)	16m 28s
build (3, mima)	4s
build (3, e2e)	6m 2s
build (3, proptest)	11m 27s
build (2_12, examples_and_formatting)	4m 22s
ci-passed	2s
	1h 5m 58s

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