mod: bump golang.org/x/sync from 0.9.0 to 0.10.0 #14967

Job	Run time
aux	4m 53s
build	14m 6s
arch (presubmit_arch_linux)	11m 28s
dashboard	3m 23s
arch (presubmit_arch_freebsd)	6m 33s
gvisor	4m 13s
arch (presubmit_arch_netbsd)	4m 22s
old	6m 43s
arch (presubmit_arch_openbsd)	4m 26s
race	8m 20s
arch (presubmit_arch_darwin)	4m 30s
race_dashboard	5m 5s
arch (presubmit_arch_windows)	3m 20s
arch (presubmit_arch_executor)	3m 15s
	1h 24m 37s

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