cargo install-update no longer works

[phil-opp]

The following error occurs:

cargo install-update
error: The subcommand 'install-update' wasn't recognized
	Did you mean 'install'?

If you believe you received this message in error, try re-running with 'cargo -- install-update'

USAGE:
    cargo [OPTIONS] [SUBCOMMAND]

For more information try --help

The suggested cargo -- install-update throws the same error. Invoking via cargo-install-update install-update still works.

> cargo --version
cargo 1.26.0-nightly (d6c3983fe 2018-03-16)
> rustc --version
rustc 1.26.0-nightly (75af15ee6 2018-03-20)

[phil-opp]

It is an issue in cargo/rustc: rust-lang/cargo#5212

[nabijaczleweli]

Second dupe of #68, nice

[phil-opp]

Sorry, I forgot to look at the closed bugs.