title: ECharts Yaxis issue
body: <p>I have a <code>ECharts</code> line chart where, based on some condition, the series can or can't have the <code>markline</code>. The problem is that, if the actual maximum yaxis value is less then a markline y value, not all the markline will be shown.</p>
  
  <p>I tried to set manually the min/max of my yaxis but nothing changes.</p>
  
  <p>This is how the axis conditions are defined in the option:</p>
  
  <pre><code>axis:[
       {
           scale: true
       }],
  xAxis: [{
            type: "time"
         }],
  yAxis: [{
             type: "value",
             axisLabel: {
                  formatter: "{value} ° C"
                  },
             scale: true
           }]
  </code></pre>
  
  <p>and this is how I set the min/max yaxis values:</p>
  
  <pre><code>termoLineCharts[index].yAxis.min = minYvalue - 15;
  termoLineCharts[index].yAxis.max = maxYValue + 15;
  </code></pre>