electron app Mac app store icon issue -> "missing required icon"

I am trying to upload mas -> .pkg file to mac app store and it is continuously giving me following error

ERROR ITMS-90236: "Missing required icon. The application bundle does not contain an icon in ICNS format, containing both a 512x512 and a 512x512@2x image. For further assistance, see the Apple Human Interface Guidelines at https://developer.apple.com/macos/human-interface-guidelines/icons-and-images/app-icon"

I have added 512*512 ICNS file and png file of icon in build.

Icon is working fine if I create DMG file. its also showing me proper icon in mac dock and its installer. So where do I exactly need to add my icon?

I was able to fix it by creating a folder called "icon.iconset". Keep two png in this folder.

For each file the image size was the same pixel dimensions. For example icon_512x512.png was 512 pixels by 512 pixels. When the file name was marked with @2x the pixel dimensions would double. So icon_512x512@2x.png would be 1024 pixels by 1024 pixels.

After ensuring that folder is setup correctly, I navigated to the folder that contained the folder I just created in Terminal and ran the following command.

iconutil --convert icns icon.iconset

This generated a .icns file