Return type mixed of method Checkout\Tests\IterableObject::getIterator() is not covariant with tentative return type Traversable of method IteratorAggregate::getIterator().

Error message "Return type mixed of method Checkout\Tests\IterableObject::getIterator() is not covariant with tentative return type Traversable of method IteratorAggregate::getIterator()." cannot be ignored, use excludePaths instead.

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. For more info: https://github.blog/changelog/2023-06-13-github-actions-all-actions-will-run-on-node16-instead-of-node12-by-default/