fix(plugin): added missing babel plugin

Author: BowlingX

package.json

@@ -19,6 +19,7 @@
     "babel-plugin-transform-es2015-classes": "^6.9.0",
     "babel-plugin-transform-proto-to-assign": "^6.9.0",
     "babel-plugin-transform-runtime": "^6.3.13",
+    "babel-plugin-transform-class-properties": "6.9.0",
     "babel-polyfill": "^6.3.14",
     "babel-preset-es2015": "^6.3.13",
     "babel-preset-stage-0": "^6.5.0",