electron-builder install-app-deps does not honor build.directories.app

[kvnsmth]

• Version: 19.6.3

• Target: macOS

The latest electron-builder install-app-deps ignores an override in build.directories.app, ie it always uses app for the directory.

I think this is because of these two lines:

https://github.com/electron-userland/electron-builder/blob/v19.6.3/packages/electron-builder/src/cli/install-app-deps.ts#L42
and
https://github.com/electron-userland/electron-builder/blob/v19.6.3/packages/electron-builder/src/util/config.ts#L59

I would expect getConfig to always call loadConfig but it doesn't when called from installAppDeps (since null is explicitly passed in). @develar I see you on the blame line so maybe you could shed some light on why it skips if packageMetadata == null?

This works as expected on 19.4.2.

[develar]

Fixed in 19.7.1, thanks.

todo: add test.