fix(build): define appName to fix this error: "The '@nextcloud/vue' library was used without setting / replacing the 'appName'"

webpack.config.js

@@ -77,6 +77,10 @@ module.exports = {
     new webpack.ProvidePlugin({
       Buffer: ['buffer', 'Buffer'],
     }),
+
+    new webpack.DefinePlugin({
+      appName: JSON.stringify(appName),
+    }),
   ],
 
   resolve: {