Additional React PropTypes Validators

The `react-prop-types` library provides a collection of supplementary validators for React's original `PropTypes` system. Introduced to extend the native `React.PropTypes` with utilities such as `elementType`, `all`, `componentOrElement`, `deprecated`, and `isRequiredForA11y`, it addresses common validation patterns not covered by React itself. The current stable version is 0.4.0, which reflects its development primarily during the React 0.14.x to early 15.x era. This package is specifically designed for use with older React applications where `PropTypes` were still part of the `react` package, rather than the separate `prop-types` package introduced with React 15.5.0. Its release cadence is effectively inactive, and it differentiates itself by offering specific, reusable validation functions for accessibility, deprecation warnings, and type checking for React components and DOM elements.