docs: fix ci for webpack.js.org

The link `https://webpack.js.org/configuration/#options:~:text=ignoreWarnings` was added in webpack-contrib#129, I think the author used it as a workaround because the URL should be used here is blocked by this pull request webpack/webpack.js.org#4076.

Now `#options:~:text=ignoreWarnings` was recognized as ID and webpack.js.org doesn't have it in the page which caused the failure of CI.

This pull request removes the paragraph temporarily to fix CI for webpack.js.org. And we can add it back later.

Author: chenxsan

README.md

@@ -135,8 +135,6 @@ module.exports = {
 };
 ```
 
-More information about the `ignoreWarnings` option you can find [here](https://webpack.js.org/configuration/#options:~:text=ignoreWarnings);
-
 ## Contributing
 
 Please take a moment to read our contributing guidelines if you haven't yet done so.