title: Angular spiderweb chart properties gridLineInterpolation give error "does not exist in type 'AxisOptions | AxisOptions[]'"
body: <p>The following code block works fine with all the properties in fiddle <a href="https://jsfiddle.net/pgc2ovdj/6/" rel="nofollow noreferrer">https://jsfiddle.net/pgc2ovdj/6/</a></p>
  
  <p>but when i use the same properties in my angular project using typescript it does not recognize the following properties
   <strong>yAxis.gridLineInterpolation</strong> and <strong>plotOptions.series.grouping</strong></p>
  
  <p>I am using the following dependencies:</p>
  
  <pre><code>"angular-highcharts": "^6.2.6",
  "highcharts": "^6.2.0",
  
  "@types/highcharts": "^5.0.31",
  </code></pre>
  
  <p><em>TypeScript Version: 2.3</em></p>
  
  <pre><code>import { Highcharts,Chart } from 'angular-highcharts';
  
  
  
  Highcharts.chart('container', {
  chart: {
      polar: true,
  },
  xAxis: {
      categories: ['Sales', 'Marketing', 'Development', 'Customer Support',
          'Information Technology', 'Administration'],
      tickmarkPlacement: 'on',
      lineWidth: 0
  },
  
  yAxis: {
      gridLineInterpolation: 'polygon',
      lineWidth: 0,
      min: 0
  },
  plotOptions: {
     series:{
          grouping: true,
          stacking:'column',
     }
  },
  tooltip: {
      shared: true,
      pointFormat: '&lt;span style="color:{series.color}"&gt;{series.name}: &lt;b&gt;${point.y:,.0f}&lt;/b&gt;&lt;br/&gt;'
  },
  
  series: [{
      name: 'Allocated Budget',
      data: [43000, 19000, 60000, 35000, 17000, 10000],
      pointPlacement: 'on'
  }, {
      name: 'Actual Spending',
      data: [50000, 39000, 42000, 31000, 26000, 14000],
      pointPlacement: 'on'
  }]
  </code></pre>
  
  <p>});</p>