remove webpack error in node_modules code example

Example: If you would prefer to ignore this check, add SKIP_PREFLIGHT_CHECK=true to an .env file in your project. That will permanently disable this message but you might encounter other issues.

// first run in terminal:
 yarn add --dev dotenv
 
// create .env file in root directory 
// then add below line in the .env file
 SKIP_PREFLIGHT_CHECK=true