docs: release notes for the v20.3.18 release #3118

Job	Run time
list	21s
workflow (build-unit-tests)	2m 34s
workflow (devkit-core-tests)	1m 30s
workflow (devkit-core-tests-rerun)	1m 23s
workflow (build-cli)	1m 59s
workflow (modules-builder-tests)	1m 58s
	9m 45s

Provide feedback