Bump version to 0.21 #582

Job	Run time
build-image-matrix	9s
composer-0-21-0 / configure-build-push	11m 24s
torch-2-0-1-cu118 / configure-build-push	10m 38s
torch-2-1-2-cu121 / configure-build-push	9m 37s
torch-2-2-1-cu121 / configure-build-push	9m 16s
torch-2-0-1-cpu / configure-build-push	3m 14s
composer-0-21-0-cpu / configure-build-push	7m 25s
torch-2-1-2-cpu / configure-build-push	4m 36s
torch-2-2-1-cpu / configure-build-push	4m 56s
torch-2-1-2-cu121-aws / configure-build-push	9m 37s
torch-2-0-1-cu118-aws / configure-build-push	9m 44s
torch-2-2-1-cu121-aws / configure-build-push	10m 33s
	1h 31m 9s

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