Type string trivially inferred from a string literal, remove type annotation

Process completed with exit code 1.

The following actions uses node12 which is deprecated and will be forced to run on node16: actions/checkout@v2, actions/setup-node@v2. For more info: https://github.blog/changelog/2023-06-13-github-actions-all-actions-will-run-on-node16-instead-of-node12-by-default/