ESLint has deprecated .eslintrc file naming convention.

[Pro777]

From https://eslint.org/docs/user-guide/configuring#configuration-file-formats

JavaScript - use .eslintrc.js and export an object containing your configuration.
YAML - use .eslintrc.yaml or .eslintrc.yml to define the configuration structure.
JSON - use .eslintrc.json to define the configuration structure. ESLint’s JSON files also allow JavaScript-style comments.
Deprecated - use .eslintrc, which can be either JSON or YAML.
package.json - create an eslintConfig property in your package.json file and define your configuration there.