`eslint-plugin-patternfly-react` - Add support for flat config format for ESLint

Currently the eslint-plugin-patternfly-react supports the ESLint v9 plugin API thanks to the work done by @kmcfaul under #10743. However it still requires the use of compatibility functions in order to transform the legacy configuration format to something that can be used in ESLint v9 due to its use of the now required flat configuration format.

The implementation of eslint-plugin-patternfly-react should be updated so it supports the new configuration format, and the documentation in the README should be updated to reflect that. For an example of this, see the documentation for the ESLint markdown plugin.

找到 eslint-plugin-patternfly-react 的实现及其 README，然后将配置指南与链接的 eslint-plugin-markdown 示例进行比较。更新插件以支持 ESLint 的 flat 配置格式，并修改 README 以记录新的用法；当实现和文档都能在无需兼容性转换的情况下与 ESLint v9 一起工作时，即表示完成。