Remove obsolete dep from demo

Author: rvsia

packages/react-renderer-demo/package.json

@@ -28,7 +28,6 @@
     },
     "dependencies": {
         "@actions/github": "^5.0.0",
-        "@babel/plugin-proposal-class-properties": "^7.12.1",
         "@data-driven-forms/form-builder": "0.0.12-rc1",
         "@data-driven-forms/mui-component-mapper": "*",
         "@data-driven-forms/react-form-renderer": "*",