Not compatible with React 19

[RomanHotsiy]

This lib relies on defaultProps (e.g. here: https://github.com/schiehll/react-alert/blob/master/src/Provider.js#L197-L206) and

In React 19, the defaultProps static property for function components has been removed in favor of ES6 default parameters. This change aims to align React with modern JavaScript practices and simplify component definitions.

Without defaultProps, the usage example from the README doesn't work (the one without explicit context) because the context is undefined here: https://github.com/schiehll/react-alert/blob/master/src/Provider.js#L139