Update free-courses-pt_BR.md (#3367)

free-courses-pt_BR.md

@@ -24,6 +24,7 @@
 * [Python](#python)
 * [React](#react)
 * [Ruby](#ruby)
+* [Sass](#sass)
 * [Shell](#shell)
 * [Swift](#swift)
 
@@ -189,6 +190,11 @@
 * [Ruby Para Iniciantes](https://www.udemy.com/ruby-para-iniciantes/) - Bruno Paulino (Udemy)
 
 
+### Sass
+
+* [Sass placeholders: o jeito certo](https://www.udemy.com/course/sass-placeholders-o-jeito-certo/) - Tárcio Zemel (Udemy)
+
+
 ### Shell
 
 * [Conceitos de Programação em Shell Script](https://www.udemy.com/conceitos-de-programacao-em-shell-script/) - TemWeb (Udemy)