--ext flag in the npm run lint command no longer supported

[DupontAchille]

The --ext flag is no longer supported when using a flat config file (eslint.config.js).
Also documented here: https://eslint.org/docs/latest/use/configure/migration-guide#--ext

In package.json "lint": "eslint . --ext ts,tsx --report-unused-disable-directives --max-warnings 0",
should be changed to "lint": "eslint . --report-unused-disable-directives --max-warnings 0",