Add support multiple font styles

Author: LitoMore

README.md

@@ -77,6 +77,13 @@ Where `[ICON NAME]` is replaced by the icon name, for example:
 <i class="si si-simpleicons si--color"></i>
 ```
 
+Or use the squared font, all font will rendered in the same-sized square:
+
+```html
+<i class="si-squared si-simpleicons"></i>
+<i class="si-squared si-simpleicons si--color"></i>
+```
+
 In this example we use the `<i>` tag, but any inline HTML tag should work as you expect.
 
 [latest-release]: https://github.com/simple-icons/simple-icons-font/releases/latest