docs: release notes for the v21.1.4 release #9779

Job	Run time
build-e2e-windows	3m 1s
lint	1m 59s
build	3m 12s
e2e-windows (24, esbuild, 3)	26s
e2e-windows (24, esbuild, 2)	28s
e2e-windows (24, esbuild, 5)	29s
e2e-windows (24, esbuild, 1)	19s
e2e-windows (24, webpack, 0)	28s
e2e-windows (24, esbuild, 4)	29s
e2e-windows (24, webpack, 3)	29s
e2e-windows (24, esbuild, 0)	26s
e2e-windows (24, webpack, 1)	28s
e2e-windows (24, webpack, 4)	28s
e2e-windows (24, webpack, 5)	29s
e2e-windows (24, webpack, 2)	19s
Browser Compatibility Tests	14s
publish-snapshots	13s
test	3s
e2e-snapshots	1s
e2e	1s
e2e-package-managers	1s
	14m 3s

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