What version of this package are you using?

standard-engine@14.0.1

What problem do you want to solve?

I don't think we should use deprecated APIs of other packages. See ESLint Node.js API.
Currently standard-engine supports any version of eslint >= 1.0.0, we should instead support any version of eslint >= 7.0.0 to be able to use the "new" ESLint class API.

What do you think is the correct solution to this problem?

Refactor to make it work with the ESLint class. (BREAKING CHANGE)
For example at this line, we're using CLIEngine :