crypto-square: replace repeated push with resize (#1025)
crypto-square: replace repeated push with resize (#1025)

clippy::same_item_push
https://rust-lang.github.io/rust-clippy/master/index.html#same_item_push

Helps address https://github.com/exercism/rust/pull/1012
petertseng/exercism-rust,exercism/xrust,petertseng/exercism-rust,petertseng/exercism-rust,exercism/xrust