In package.json, add engines section with node >=20

Author: cliffhall

package.json

@@ -85,5 +85,8 @@
     "nightwatch": "^3.3.2",
 	"prettier": "^3.5.1",
     "rollup": "4.22.4"
+  },
+  "engines": {
+	"node": ">=20"
   }
 }