title: Add space above y-axis without expand()
body: <p>When plotting percentages and a column is at 100%, the value label gets cut of from the graph.</p>
  
  <p><a href="https://i.stack.imgur.com/sZ8Qq.png" rel="noreferrer"><img src="https://i.stack.imgur.com/sZ8Qq.png" alt="enter image description here"></a></p>
  
  <p>Two possible solutions to this are:<br>
  1. <code>scale_y_continuous(limits = c(0, 1.1)</code><br>
  2. <code>scale_y_continuous(expand = c(0, 0, 0.2, 0)</code><br>
  But both solutions expand the axis. I would prefer to just add a padding/margin so that I don't get a long line above 100%. Is this possible?
  <a href="https://i.stack.imgur.com/WcxPA.png" rel="noreferrer"><img src="https://i.stack.imgur.com/WcxPA.png" alt="enter image description here"></a></p>
  
  <p><strong>Working example</strong></p>
  
  <pre><code>library(ggplot2)
  library(magrittr)
  data.frame("value" = c(0, 0.5, 1),
             "v1" = letters[1:3]) %&gt;% 
          ggplot(aes(x = v1, 
                     y = value, 
                     label = value)) +
          geom_bar(stat = "identity") + 
          geom_text(stat = "identity",
                    vjust = -1) + 
          scale_y_continuous(breaks = seq(0, 1, 0.2), 
                             limits = c(0, 1),
                             labels = scales::percent, 
                             expand = c(0, 0, 0.2, 0)) + 
          theme_classic()
  </code></pre>