Upgrade to eslint v9

[Pharb]

• using recommended npx @eslint/migrate-config .eslintrc
• https://eslint.org/docs/latest/use/configure/migration-guide

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 100.00%. Comparing base (536b97b) to head (f4f2fb1). Report is 2 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #254 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 9 9 Lines 738 738 Branches 135 135 ========================================= Hits 738 738 ```

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