windows-installer program finds resources/app.asar which is not true for electron-forge made apps

`electron-forge package` creates exe file which has _**resources/electron.asar**_
I went into DEBUG mode and found that the winstaller tries to find for **_resources/app.asar_** when the appDirectory is specified.

It would be good to have a condition or flag to assign the name of asar rather then keeping a static value as app.asar which I found in the _lib/index.js_ of the source code.

Also, is there a precondition that the package needs to be built in specific way? electron-forge uses electron-packager in behind.