gnu: Remove rust-bincode-1.1.

gnu: Remove rust-bincode-1.1.

* gnu/packages/crates-io.scm (rust-bincode-1.1): Remove variable.
(rust-encoding-rs-0.8, rust-generic-array-0.13, rust-parking-lot-0.10,
rust-parking-lot-0.9, rust-parking-lot-0.8, rust-parking-lot-0.7,
rust-rand-0.5, rust-rand-isaac-0.2, rust-rand-isaac-0.1,
rust-rand-pcg-0.2, rust-rand-pcg-0.1, rust-rand-xorshift-0.2,
rust-rand-xorshift-0.1, rust-rand-xoshiro-0.4, rust-rand-xoshiro-0.3,
rust-serde-bytes-0.11, rust-smallvec-1, rust-smallvec-0.6,
rust-uuid-0.7) [arguments]: Replace rust-bincode-1.1 with 1.2.