Add guide "Go por Exemplo" to Brazilian list (#5459)

Source: http://goporexemplo.golangbr.org

Bump. Recover Resolves EbookFoundation/free-programming-books#5451

Co-Authored-By: Gustavo  <49646779+gustavors22@users.noreply.github.com>

Co-authored-by: Gustavo  <49646779+gustavors22@users.noreply.github.com>

books/free-programming-books-pt_BR.md

@@ -135,6 +135,7 @@
 
 * [Aprenda Go com Testes](https://larien.gitbook.io/aprenda-go-com-testes) - Lauren Ferreira
 * [Go - hands on](https://github.com/go-br/estudos)
+* [Go por Exemplo](http://goporexemplo.golangbr.org) - Mark McGranaghan, Jeremy Ashkenas, golangbr, Daniela Tamy Iwassa (HTML)
 
 
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