Configuration mode window added accept shortcut to Enter button

ubinstall-gtk-configuration-mode.glade

@@ -172,6 +172,7 @@
             <property name="visible">True</property>
             <property name="can-focus">True</property>
             <property name="receives-default">True</property>
+            <accelerator key="Return" signal="clicked"/>
           </object>
           <packing>
             <property name="pack-type">end</property>