rust: update test_case crate

rust: update test_case crate

fixes unused_unit

warning: unneeded unit expression
   --> src/bittorrent_dht/parser.rs:590:5
    |
590 | /     #[test_case(
591 | |         b"",
592 | |         "Error: discovered Dict but expected EOF" ;
593 | |         "test parse bittorrent dht packet err 1"
594 | |     )]
    | |______^