Update package.json
Update package.json

Spelling Mistake in the Code Signing header for OS X causing it not to build.
RocketChat/Rocket.Chat.Electron,ZedTheYeti/Rocket.Chat.Electron,RocketChat/Rocket.Chat.Electron,ZedTheYeti/Rocket.Chat.Electron,ZedTheYeti/Rocket.Chat.Electron,RocketChat/Rocket.Chat.Electron