Possible incorrect URL concat for Electron Release Server

[msholly]

I loved the more robust "app-ness" of SkelEktron vs the Electron Boilerplate, so I merged your main process and especially the update logic into my existing app. Since Electron Release Server is the primary provider for updates, I think the URL is incorrect in your update.js file.

const platform = os.platform() + '_' + os.arch()

Builds out download.domain.com/update/win32_x64/0.1.7/RELEASES

But Electron Release Server is expecting no _x64 in the URL. Docs: https://github.com/PierBover/electron-release-server/blob/506f05fceca4b5f52858ae124ae3678d2334efde/docs/update-windows.md

I added a new simpler constant const platformSimple = os.platform() and plugged that into the updaterFeedURL variable.

It now returns the proper update/win32/0.1.7/RELEASES URL and not a 404.

I prefaced this report with the fact I merged your code, and haven't had the chance to do a test on your vanilla platform with your setup instructions for S3 and so on.