Merge pull request #16137 from riteshsp2000/fix/#14492

fix: add a note to install the webrick gem for Ruby 3.0 users

Author: vgrl

content/pages/setting-up-a-github-pages-site-with-jekyll/testing-your-github-pages-site-locally-with-jekyll.md

@@ -50,6 +50,12 @@ Before you can use Jekyll to test a site, you must:
   ```
 3. To preview your site, in your web browser, navigate to `http://localhost:4000`.
 
+{% note %}
+
+**Note:** If you are using Ruby 3.0 and Jekyll 4.2.x or older, you will need to add the `webrick` gem to your project's Gemfile prior to running `bundle install`.
+
+{% endnote %}
+
 ## Updating the {% data variables.product.prodname_pages %} gem
 
 Jekyll is an active open source project that is updated frequently. If the `github-pages` gem on your computer is out of date with the `github-pages` gem on the {% data variables.product.prodname_pages %} server, your site may look different when built locally than when published on {% data variables.product.product_name %}. To avoid this, regularly update the `github-pages` gem on your computer.