Fix test (#278)

Author: Ash-Crow

content_manager/tests/test_blocks.py

@@ -167,7 +167,7 @@ def test_card_with_cta_buttons(self):
                     <a class="fr-btn fr-btn--secondary"
                     href="https://numerique.gouv.fr"
                     target="_blank"
-                    rel="noopener external">Label</a>
+                    rel="noopener external">Label <span class="fr-sr-only">Ouvre une nouvelle fenêtre</span></a>
                 </li>
             </ul>""",
             response.content.decode(),