Finish pushing the minimum Rust to 1.31.0
Finish pushing the minimum Rust to 1.31.0

nipunn1313/cargo,vojtechkral/cargo,rust-lang/cargo,rust-lang/cargo,tshepang/cargo,tsurai/cargo,nipunn1313/cargo,rust-lang/cargo,rustyhorde/cargo,eminence/cargo,nipunn1313/cargo,rustyhorde/cargo,tsurai/cargo,vojtechkral/cargo,eminence/cargo,eminence/cargo,tshepang/cargo,tsurai/cargo,nipunn1313/cargo,rustyhorde/cargo,eminence/cargo,tsurai/cargo,rust-lang/cargo,tshepang/cargo,tshepang/cargo,vojtechkral/cargo,tsurai/cargo,rustyhorde/cargo,vojtechkral/cargo