This updates encoding_rs, crossbeam-utils and crossbeam-channel. This
serves two purposes. The encoding_rs update fixes a compilation failure
on the latest nightly. The crossbeam updates are good sense and to
reduce duplicate dependencies such as cfg-if. (Although, we note that
the log crate still pulls in cfg-if 0.1, so ripgrep has a duplicate
dependency there for now. But it's very small.)
Fixes#1721, Closes#1705
3ef63dacbe