docs: release notes for the v20.2.1 release #1739

Job	Run time
list	26s
workflow (modules-builder-tests)	2m 5s
workflow (devkit-core-tests)	1m 12s
workflow (devkit-core-tests-rerun)	1m 26s
workflow (build-cli)	1m 27s
workflow (build-unit-tests)	2m 33s
	9m 9s

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