chore: add support for eslint v9

[nelli91]

I give it a try to update ESLint to v9.

I followed the official ESLint guide for making the plugin compatible with flat config

What includes:

• Create new file structure required by ESLint flat config.
• Refactor rules in order to replace parserOptions with languageOptions.
• Backward compatibility by still exporting environments key and exporting old configs using -legacy as suggested in migration guide.
• Update ESLint to v9 and eslint-plugin- dependencies.
• Delete old eslintrc and add a new eslint.config.js.
• Add test-v9 in circle.yml (not sure if needed I followed what you already have)
• Update README.

Closes

TODO:

• 3 Tests are failing because it doesn't find the rule

// disable the eslint rule
    {
      code: `
        cy.wait(100); // eslint-disable-line no-unnecessary-waiting
      `,
      languageOptions,
    },
    {
      code: `
        /* eslint-disable-next-line no-unnecessary-waiting */
        cy.wait(100)
      `,
      languageOptions,
    },
    {
      code: `
        /* eslint-disable no-unnecessary-waiting */
        cy.wait(100)
        /* eslint-enable no-unnecessary-waiting */
      `,
      languageOptions,
    }

[MikeMcC399]

@nelli91

Thanks for your contribution to getting the repo updated to support ESLint v9 flat files! This helped me get up to speed on the conversion.

ESLint v9 flat files are fully supported since v3.3.0 in May 2024.