-DEXPERIMENTAL_VERSION can be used to specify (non-zero) experimental version. It will show as LEAD.MAJOR-MINOR. It will also set the (experimental) suffix in Cemu's name. If not specified, the suffix will be empty and the version shows as LEAD.MAJOR
If PUBLIC_RELEASE is not set the suffix will be (dev)
Also updated the auto-updater to use a new API that supports our github releases