docs: release notes for the v21.1.2 release #2661

Job	Run time
lint	2m 3s
build	30s
build-e2e-windows	30s
Browser Compatibility Tests	0s
test	0s
e2e-package-managers	0s
e2e-snapshots	0s
e2e	0s
publish-snapshots	0s
e2e-windows	-1s
	3m 2s

Provide feedback