Add mime type for ASAR Electron archives
Archives used by Electron https://github.com/electron/asar
There's not really been a general consensus by the project but there's been suggestions about using application/x-asar
, see also see https://github.com/electron/asar/issues/199 and https://github.com/sindresorhus/file-type/pull/378#issuecomment-660592360