Add eslint

[Luis Herranz]

Add eslint with this eslint.config.js file:

module.exports = {
  parser: "@typescript-eslint/parser",
  extends: [
    "eslint:recommended",
    "plugin:import/recommended",
    "plugin:jest/recommended",
    "plugin:@typescript-eslint/recommended"
  ],
  rules: {
    "@typescript-eslint/indent": "off"
  },
  env: {
    node: true,
    es6: true
  },
  settings: {
    "import/resolver": {
      node: {
        extensions: [".js", ".jsx", ".ts", ".tsx"]
      }
    }
  }
};

[Luis Herranz]

Fixed in 72b8672.