fix: add height: 100% for vertical orientation

Without the `height` property the element will always use the `min-height` property.
Now the `.rangeslider` element will take the whole space of its parent or just the defined `min-height`.

src/rangeslider.scss

@@ -29,6 +29,7 @@ $rangeslider__handle:       ".rangeslider__handle";
     width: 20px;
     min-height: 150px;
     max-height: 100%;
+    height: 100%;
 }
 
 #{$rangeslider--disabled} {