ElectronNET.Core 0.4.0

ElectronNET.Core

• Fixed ElectronSingleInstance handling (#996) @softworkz
• Fixed PackageId handling (#993, #995) @softworkz
• Added cross-platform npm restore and check mismatch on publish (#988) @softworkz
• Released 0.4.0 by @FlorianRappl in #998

Full Changelog: 0.3.1...0.4.0