Workshop mods have a more complex layout - versions.sii etc.
In normal mods you specify `compatible_versions` in the manifest.sii file, however, for Steam Workshop mods you specify a `compatible_versions` array in the versions.sii file.
When you are creating a standard mod you need to take care about its distribution, and the users of the mod need to take care of downloading the up-to-date version. Meanwhile, Steam Workshop mods are automatically downloaded for each mod subscriber when you upload a new version to the workshop.