breaking change in /construction/derive

[Ljzn]

Hi, we're using the Dfinity rosetta node in production, and we noticed a breaking change in protocol recently.

Before version v1.2.0, the /construction/derive/ can be called without metadata. After v1.2.0, there will be an error said "account_type is missing".

The reason might be this code:

rosetta-node/rosetta-api/src/models.rs

Line 577 in f33f013

pub account_type: AccountType,

We suggest note the breaking changes like this in document or changelog.