diffie-hellman: Added Cargo.toml to config.json (#1433)
diffie-hellman: Added Cargo.toml to config.json (#1433)

Hopefully, this will allow the user to add dependencies (e.g. rand, num_bigint, etc.).  Not sure how to test this for breakage other than simply committing it and testing it on Exercism.
petertseng/exercism-rust,petertseng/exercism-rust,petertseng/exercism-rust