@oclif/errors should be a dependency

[aparajita]

See this line:

import {CLIError, error, exit, warn} from '@oclif/errors'

@oclif/errors must be declared as a dependency, not a devDependency. The only reason you aren't getting bitten by this (mostly) is because the current implementation of npm and yarn are shamelessly flattening the package hierarchy, thus hiding missing dependency declarations.

[HosseinAgha]

I encountered this error when using Apollo CLI and yarn pnp. The problem is that your package relies on a none standard behaviour for dependency resolution.
Pinging @arcanis As suggested in pnp troubleshooting page.

[arcanis]

Related: oclif/oclif#150