[v2] Block plugin installation if compatibility is not stated

[Stanzilla]

Many plugins will break with the release of v2, to prevent users from suffering from incompatible plugins and their errors/slowdowns, we should block installation/loading if they do not specify a certain tag in their package.json file. That tag could be something like

requiresHyperVersion: >2,

Discuss!

[timothyis]

Hmm, this is interesting. cc @chabou. We discussed before about having better plugin management for versions.

[chabou]

@timothyis @albinekb @Stanzilla If we want to use engines mechanism, we need to inject hyper version in process.version.
Easy for application but we need to inject it too when running embedded yarn. Here: https://github.com/zeit/hyper/blob/bf2d6ea8555e3a4e40e4c8df34cbe1963282d1fd/app/plugins/install.js#L19-L37

I think that the only solution is to use -r option when launching electron as node, to require a module that will inject version.

We need to check this field when requiring plugins too with some semver comparison.

[Stanzilla]

Sounds good to me.