Update builder.go

[cpucorecore]

this will lose block when newRoot.AddChild returns err. in ipfs-cluster single dag service add(context.TODO(), node) maybe failed when not enough peers to allocate for this block node

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[lidel]

@Jorropo you may be most familiar to review this.

[Jorropo]

LGTM Ty 🎉

[Jorropo]

@cpucorecore do you need a release of this ?

[cpucorecore]

@cpucorecore do you need a release of this ?

thank u for your quick and nice reply.
yes, please release it if it's convenient