Remove console.logs

Using console in production is generally undesirable due to
performance loss and security concerns. Errors were changed
to console.error and console.logs were removed.

lib/main-app.js

@@ -59,7 +59,7 @@ updater.on('update-downloaded', (info) => {
 })
 
 updater.autoUpdater.on('error', (err) => {
-  console.log(err)
+  console.error(err)
 })
 
 ipc.on('update-app-confirm', function (event, msg) {