Missing electron peer dependency

[guillaumearm]

We should add electron compatible version range in peerDependencies

"peerDependencies": { "electron": ">=1.7.1 <=2.02" }

Additionally it can be a good thing to add electron@2.0.2 in devDependencies to fix unit tests.

[grantcv1]

The peer dependencies are now set to:

"peerDependencies": {
"electron": ">=17.1 <3.x.x"
},

It seems it should read >=1.7.1 rather than >=17.1 and it would be really helpful if the other end could be upgraded to <6