title: The type 'variwide' in highcharter does not work
body: <p>I would like to create a variwide chart in Highcharter to use in R,but the result is empty。</p>
  
  <pre><code>library(data.table)
  library(highcharter)
  
  labor_cost &lt;- data.table(country =c('挪威','丹麦','比利时','瑞典','法国','荷兰','芬兰','德国','奥地利','爱尔兰','意大利','英国','西班牙','希腊','葡萄牙','捷克共和国','波兰','罗马尼亚'),cost=c(50.2,42,39.2,38,35.6,34.3,33.2,33,32.7,30.4,27.8,26.7,21.3,14.2,13.7,10.2,8.6,5.5),gdp=c(335504,277339,421611,462057,2228857,702641,215615,3144050,349344,275567,1672438,2366911,1113851,175887,184933,176564,424269,169578))
  
  highchart() %&gt;%
  hc_title(text = "欧洲各国人工成本", align="center")%&gt;%
  hc_xAxis(type = "category",title = list(text = "* 柱子宽度与 GDP 成正比")) %&gt;%
  hc_legend(enabled = FALSE) %&gt;%
  hc_add_series(data = labor_cost,type = "variwide",hcaes(x = country,width= gdp),dataLabels = list(enabled = TRUE,format="€{point.y:.0f}"),colorByPoint = TRUE)
  </code></pre>
  
  <p>The code executes normally，no errors appear.</p>