eth.Transaction: `v` field is not present in 4844 txs

[ryanschneider]

go-ethlibs/eth/transaction.go

Line 33 in 8b8f17d

V Quantity `json:"v"`

We should either make it *Quantity or perhaps support omitempty on Quantity fields, not sure which is better yet, probably *Quantity is more correct but is a breaking change.