We still need to decide how to handle non-specfic `chainId` in the JSON
encoding of authorizations. With `chainId` being a uint64, the previous
implementation just used value zero. However, it might actually be more
correct to use the value `null` for this case.
This PR implements EIP-7702: "Set EOA account code".
Specification: https://eips.ethereum.org/EIPS/eip-7702
> Add a new transaction type that adds a list of `[chain_id, address,
nonce, y_parity, r, s]` authorization tuples. For each tuple, write a
delegation designator `(0xef0100 ++ address)` to the signing account’s
code. All code reading operations must load the code pointed to by the
designator.
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Co-authored-by: Mario Vega <marioevz@gmail.com>
Co-authored-by: Martin Holst Swende <martin@swende.se>
Co-authored-by: Felix Lange <fjl@twurst.com>
