fix compilation error by adding missing crate feature

[KirillLykov]

Problem

process_new_order_v3 method is available only for feature program. crank depends on serum_dex crate, but doesn't use aforementioned feature and, hence, fails with error:

Self::process_new_order_v3,
     |                       ^^^^^^^^^^^^^^^^^^^^
     |                       |
     |                       variant or associated item not found in `state::State`
     |                       help: there is an associated function with a similar name: `process_cancel_order_v2`

Solution

Add the missing feature to Cargo.toml