Fixed up assertion for encodedUrl

lib/electron-launcher.js

@@ -28,7 +28,7 @@ program.allowUnknownOption();
 // Parse and assert our arguments
 program.parse(process.argv);
 assert(program.userDataDir, 'Expected `--user-data-dir` to be provided but it was not.');
-assert(program.url, 'Expected `--url` to be provided but it was not.');
+assert(program.encodedUrl, 'Expected `--encoded-url` to be provided but it was not.');
 
 // When all windows are closed, exit out
 app.on('window-all-closed', function handleWindowsClosed () {