Example Usage in README does not reflect changes in ESLint v9.0.0

[stevepolitodesign]

The release of ESLint v9.0.0 made it so flat config is the new default.

This means that the example usage in the README is outdated, and would result in the following error:

Oops! Something went wrong! :(

ESLint: 9.0.0

Error: Could not find config file.
    at locateConfigFileToUse (/Users/polito/Desktop/suspenders_qa_0/node_modules/eslint/lib/eslint/eslint.js:349:21)
    at async calculateConfigArray (/Users/polito/Desktop/suspenders_qa_0/node_modules/eslint/lib/eslint/eslint.js:384:49)
    at async ESLint.lintFiles (/Users/polito/Desktop/suspenders_qa_0/node_modules/eslint/lib/eslint/eslint.js:814:25)
    at async Object.execute (/Users/polito/Desktop/suspenders_qa_0/node_modules/eslint/lib/cli.js:461:23)
    at async main (/Users/polito/Desktop/suspenders_qa_0/node_modules/eslint/bin/eslint.js:165:22)
error Command failed with exit code 2.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
app/assets/stylesheets/application.postcss.cssERROR: "lint:eslint" exited with 2.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.