minor #168 Update README.rst (benoitMariaux)

This PR was merged into the 2.0-dev branch.

Discussion
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Update README.rst

Because h2 tags do not have a .post class.

Commits
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6a04780 Update README.rst

README.rst

@@ -73,7 +73,7 @@ Extract data:
 .. code-block:: php
 
     // Get the latest post in this category and display the titles
-    $crawler->filter('h2.post > a')->each(function ($node) {
+    $crawler->filter('h2 > a')->each(function ($node) {
         print $node->text()."\n";
     });