[ADD] docs for webextension-polyfill

Author: JohnBra

README.md

@@ -41,6 +41,7 @@ well with this template. [Check it out here](https://gist.github.com/JohnBra/c81
 - [TypeScript](https://www.typescriptlang.org/)
 - [Tailwind CSS](https://tailwindcss.com/)
 - [i18n (optional)](https://developer.chrome.com/docs/extensions/reference/api/i18n)
+- [Cross browser development with polyfill (optional)](https://github.com/mozilla/webextension-polyfill?tab=readme-ov-file#basic-setup-with-module-bundlers)
 - [ESLint](https://eslint.org/)
 - [Chrome Extension Manifest Version 3](https://developer.chrome.com/docs/extensions/mv3/intro/)
 - [Github Action](https://github.com/JohnBra/vite-web-extension/actions/workflows/ci.yml) to build and zip your extension (manual trigger)
@@ -171,6 +172,7 @@ To run the workflow do the following:
 - [Vite Plugin](https://vitejs.dev/guide/api-plugin.html)
 - [Chrome Extension with manifest 3](https://developer.chrome.com/docs/extensions/mv3/)
 - [Chrome Extension i18n](https://developer.chrome.com/docs/extensions/reference/api/i18n#description)
+- [Cross browser development with webextension-polyfill](https://github.com/mozilla/webextension-polyfill?tab=readme-ov-file#webextension-browser-api-polyfill)
 - [Rollup](https://rollupjs.org/guide/en/)
 - [@crxjs/vite-plugin](https://crxjs.dev/vite-plugin)
 - [Tailwind CSS](https://tailwindcss.com/docs/configuration)