Update imagemin dependencies

[mcorossigo]

Hello @douglasjunior

This is not a super critical request, but better safe than sorry. Looking through the depencencies of your project I noticed that a couple of imagemin (and imagemin itself) got some new major releases.

The fact the the last update is almost one year old, also gave time to Electron to deprecate v2.0.0.

So can you make a new release with a round of updated dependencies? Thank you!