Update coursier to 2.1.8 #1962

Job	Run time
conformance	1m 29s
build (2_12, mima)	1m 10s
build (2_12, e2e)	8s
build (2_12, test)	9m 26s
build (2_13, mima)	1m 9s
build (2_13, e2e)	8s
build (2_13, test)	9m 11s
build (3, mima)	5s
build (3, e2e)	5s
build (3, test)	8m 25s
build (2_12, examples_and_formatting)	2m 42s
build (2_13, scala3_compat_test)	6m 22s
build (3, scala3_compat_test)	7m 38s
ci-passed	1s
	47m 59s

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