fix(playground): use default 3000 port for dashboard app as it's more appropriate

Author: paveltiunov

packages/cubejs-playground/package.json

@@ -36,7 +36,7 @@
     "whatwg-fetch": "^3.0.0"
   },
   "scripts": {
-    "start": "node generateScaffolding.js && react-app-rewired start",
+    "start": "node generateScaffolding.js && PORT=3080 react-app-rewired start",
     "build": "node generateScaffolding.js && react-app-rewired --max-old-space-size=2048 build && rm -Rf ../cubejs-server-core/playground/** && cp -R build/ ../cubejs-server-core/playground/",
     "test": "node generateScaffolding.js && react-app-rewired test",
     "eject": "node generateScaffolding.js && react-scripts eject"

packages/cubejs-server-core/core/DevServer.js

@@ -208,7 +208,7 @@ class DevServer {
       res.json({ toInstall });
     }));
 
-    const dashboardAppPort = this.cubejsServer.options.dashboardAppPort || 3050;
+    const dashboardAppPort = this.cubejsServer.options.dashboardAppPort || 3000;
 
     app.get('/playground/start-dashboard-app', catchErrors(async (req, res) => {
       this.cubejsServer.event('Dev Server Start Dashboard App');