chore(package): update electron to version 4.0.0
chore(package): update electron to version 4.0.0

Closes #1523
feross/webtorrent-app,webtorrent/webtorrent-desktop,feross/webtorrent-app,webtorrent/webtorrent-desktop,feross/webtorrent-app,webtorrent/webtorrent-desktop