Bump version to "v21.0.0-rc.5" with changelog. #10021

Job	Run time
build	5m 17s
analyze	7s
build-e2e-windows-subset	5m 29s
lint	2m 23s
test	5m 47s
e2e-package-managers (ubuntu-latest-4core, 22, yarn, 1)	6m 12s
e2e-package-managers (ubuntu-latest-4core, 22, yarn, 2)	7m 15s
e2e-package-managers (ubuntu-latest-4core, 22, yarn, 0)	8m 24s
e2e-package-managers (ubuntu-latest-4core, 22, pnpm, 0)	6m 21s
e2e-package-managers (ubuntu-latest-4core, 22, pnpm, 2)	5m 59s
e2e-package-managers (ubuntu-latest-4core, 22, pnpm, 1)	4m 50s
e2e (ubuntu-latest, 22, npm, 2)	11m 0s
e2e (ubuntu-latest, 22, npm, 0)	11m 18s
e2e (ubuntu-latest, 22, npm, 3)	8m 32s
e2e (ubuntu-latest, 22, npm, 1)	11m 57s
e2e (ubuntu-latest, 22, esbuild, 0)	7m 54s
e2e (ubuntu-latest, 22, esbuild, 1)	9m 30s
e2e (ubuntu-latest, 22, npm, 4)	9m 1s
e2e (ubuntu-latest, 22, esbuild, 3)	10m 46s
e2e (ubuntu-latest, 22, esbuild, 5)	7m 12s
e2e (ubuntu-latest, 22, npm, 5)	10m 16s
e2e (ubuntu-latest, 22, esbuild, 2)	9m 25s
e2e (ubuntu-latest, 22, esbuild, 4)	7m 7s
e2e-snapshots	-1s
e2e-windows-subset	4m 35s
	2h 56m 36s

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