Change ColorPickerInputFormatsTest for use Keys.RETURN.

Change-Id: Ic8ad7163d35e0e1c2d44e928cd52ca66a637b7fa

uitest/src/com/vaadin/tests/components/colorpicker/ColorPickerInputFormatsTest.java

@@ -87,7 +87,7 @@ public class ColorPickerInputFormatsTest extends MultiBrowserTest {
         field.sendKeys(value);
 
         // Submit
-        field.sendKeys(Keys.ENTER);
+        field.sendKeys(Keys.RETURN);
     }
 
     private String getColorpickerValue() {