Upgrade go version to 1.21.0 #7919

Job	Run time
build	5m 50s
lint	24m 7s
test	38m 27s
integration-configs-db	2m 55s
integration (requires_docker)	6m 31s
integration (integration_alertmanager)	4m 49s
integration (integration_backward_compatibility)	10m 23s
integration (integration_memberlist)	9m 21s
integration (integration_querier)	17m 1s
integration (integration_ruler)	4m 59s
integration (integration_query_fuzz)	3m 34s
deploy_website	0s
deploy	0s
	2h 7m 57s

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