Update sbt-scalajs, scalajs-compiler, ... to 1.20.1 in 0.11.x #2839

Job	Run time
conformance	4m 6s
build (2_12, mima)	1m 17s
build (2_12, e2e)	3m 16s
build (2_13, e2e)	4m 7s
build (2_13, test)	10m 45s
build (2_13, mima)	1m 28s
build (2_12, test)	10m 2s
build (3, test)	9m 38s
build (3, mima)	7s
build (2_12, examples_and_formatting)	2m 49s
build (3, e2e)	4m 23s
build (2_13, scala3_compat_test)	6m 40s
build (3, scala3_compat_test)	10m 23s
ci-passed	2s
	1h 9m 3s

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