Fix link Symfony 5 and add link Symfony 6 (#9310)

* Fix link symfony 5 and add link symfony 6

* Update books/free-programming-books-fr.md
Co-authored-by: NEric Hellman <eric@hellman.net>

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Co-authored-by: NEric Hellman <eric@hellman.net>

books/free-programming-books-fr.md

@@ -254,7 +254,8 @@
 
 #### Symfony
 
-* [En route pour Symfony 5](https://symfony.com/doc/5.0/the-fast-track/fr/index.html) - Fabien Potencier
+* [En route pour Symfony 5.4](https://symfony.com/doc/5.4/the-fast-track/fr/index.html) - Fabien Potencier
+* [En route pour Symfony 6.2](https://symfony.com/doc/current/the-fast-track/fr/index.html) - Fabien Potencier
 
 
 ### Processing