fix(ui): max listeners error

Author: Guillaume Chau

packages/@vue/cli-service/lib/commands/ui.js

@@ -13,6 +13,7 @@ module.exports = api => {
         typeDefs: require.resolve('@vue/cli-ui/src/graphql-api/type-defs.js'),
         resolvers: require.resolve('@vue/cli-ui/src/graphql-api/resolvers.js'),
         context: require.resolve('@vue/cli-ui/src/graphql-api/context.js'),
+        pubsub: require.resolve('@vue/cli-ui/src/graphql-api/pubsub.js'),
         server: require.resolve('@vue/cli-ui/src/graphql-api/server.js')
       }
     }

packages/@vue/cli-ui/src/graphql-api/pubsub.js

@@ -1,4 +1,5 @@
 const { PubSub } = require('graphql-subscriptions')
 
 const pubsub = new PubSub()
+pubsub.ee.setMaxListeners(0)
 module.exports = pubsub