Request to add a platform parameter to the optionsForFile option

[DIYgod]

I use the ci parameter to pass a dynamic platform and need to use different entitlements for the darwin and mas platforms, but I found that the optionsForFile option can only get the filePath and not the platform. This causes a lot of trouble for our configuration, so I would like to request adding a platform parameter to optionsForFile.

https://github.com/electron/osx-sign/blob/757fa60716efd7310006153c55172fdcec46452a/src/sign.ts#L209