Merge pull request #223 from alexislefebvre/use-github-note-on-installation-doc

use a github note on installation doc

Author: alexislefebvre

doc/installation.md

@@ -10,7 +10,7 @@ Installation
     $ composer require --dev liip/test-fixtures-bundle:^2.0.0
     ```
 
-    If you use Symfony 3.4, see the [documentation for 1.x](https://github.com/liip/LiipTestFixturesBundle/blob/1.x/README.md).
+    >**Note** If you use Symfony 3.4, see the [documentation for 1.x](https://github.com/liip/LiipTestFixturesBundle/blob/1.x/README.md).
 
     This command requires you to have Composer installed globally, as explained
     in the [installation chapter](https://getcomposer.org/doc/00-intro.md)