Исправлена опечатка в Cases_article.md

Author: osipxd

cases/Cases_article.md

@@ -1,3 +1,3 @@
 **Практические кейсы**: <br>
-1. [Аутенфикация](https://github.com/AndroidArchitecture/AndroidArchitectureBook/blob/master/cases/auth/Auth_article.md)
+1. [Аутентификация](https://github.com/AndroidArchitecture/AndroidArchitectureBook/blob/master/cases/auth/Auth_article.md)
 2. [Визарды](https://github.com/AndroidArchitecture/AndroidArchitectureBook/blob/master/cases/wizards/Wizards_article.md)