chore: alias rollup-dev to watch for development (#4615)

package.json

@@ -22,6 +22,7 @@
     "rollup": "babel-node build/rollup.js",
     "rollup-minify": "babel-node build/rollup.js --minify",
     "rollup-dev": "babel-node build/rollup.js --watch",
+    "watch": "npm run rollup-dev",
     "assets": "node build/assets.js",
     "change": "grunt chg-add",
     "clean": "grunt clean",