Hi Narendran,
When you run the Pluggable Widget Generator command : npm install @mendix/generator-widget -g
it will install the latest version by default, but right now there is an issue in this. So for time being you can degrade the version like 8.9.0 .
Refer the below Github link :
https://github.com/mendix/widgets-resources/issues/285
Version Related :
https://www.npmjs.com/package/@mendix/generator-widget/v/8.9.0