Update index.html (FusionGen#54)

Change recommended to required
Suggests that you could also use a newer version

Author: Err0r1

install/index.html

@@ -136,7 +136,7 @@ <h4>Folder Permissions</h4>
 
 										<div class="php-version">
 											<h4>PHP Version</h4>
-											Recommended PHP Version: 7.1 <span class="check-result"></span>
+											Required PHP Version: 7.1 <span class="check-result"></span>
 										</div>
 
                                         <div class="php-extensions">