gulpfile deleted babel infra: run with modern node instead

package.json

@@ -63,7 +63,7 @@
     "eslint-plugin-promise": "^3.3.1",
     "eslint-plugin-react": "^7.4.0",
     "eslint-plugin-standard": "^2.0.1",
-    "gulp": "^3.8.10",
+    "gulp": "^4.0.0",
     "gulp-concat": "^2.4.1",
     "gulp-if": "^2.0.0",
     "gulp-imagemin": "~2.4.0",