docs: release notes for the v21.0.0-rc.3 release #9927

Job	Run time
lint	2m 34s
analyze	7s
build-e2e-windows-subset	2m 22s
build	2m 24s
e2e-windows-subset	3m 58s
test	4m 1s
e2e-package-managers (ubuntu-latest, 22, yarn, 0)	12m 2s
e2e-package-managers (ubuntu-latest, 22, yarn, 1)	6m 17s
e2e-package-managers (ubuntu-latest, 22, yarn, 2)	7m 2s
e2e-package-managers (ubuntu-latest, 22, pnpm, 0)	6m 5s
e2e-package-managers (ubuntu-latest, 22, pnpm, 1)	4m 41s
e2e (ubuntu-latest, 22, npm, 0)	11m 16s
e2e (ubuntu-latest, 22, npm, 5)	10m 32s
e2e-package-managers (ubuntu-latest, 22, pnpm, 2)	5m 48s
e2e (ubuntu-latest, 22, npm, 3)	8m 31s
e2e (ubuntu-latest, 22, npm, 1)	11m 49s
e2e (ubuntu-latest, 22, npm, 2)	11m 0s
e2e (ubuntu-latest, 22, esbuild, 1)	9m 57s
e2e (ubuntu-latest, 22, esbuild, 0)	7m 52s
e2e (ubuntu-latest, 22, esbuild, 4)	6m 15s
e2e (ubuntu-latest, 22, esbuild, 2)	8m 59s
e2e (ubuntu-latest, 22, esbuild, 3)	8m 35s
e2e (ubuntu-latest, 22, esbuild, 5)	7m 12s
e2e (ubuntu-latest, 22, npm, 4)	9m 12s
e2e-snapshots	0s
	2h 48m 31s

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