[MV3] WebExtensionManifestBackgroundC3Type interface should support type: "module" optional property

[Luca Castellone]

https://developer.chrome.com/docs/extensions/mv3/intro/mv3-migration/#man-sw
Currently i get Object literal may only specify known properties, and 'type' does not exist in type WebExtensionManifestBackgroundC3Type

[Lusito]

Thanks for the report, will be fixed with the next version