title: Chart js data label anchor not changing
body: <p>I am using chartjs-plugin-datalabels to display data labels in stacked bar chart using Chart.js</p>
  <pre><code>const stackedConfig = {
     type: 'bar',
     data: {
        labels: ['Manager 1', 'Manager 2', 'Manager 3', 'Manager 4', 'Manager 5'],
        datasets: [{
           label: 'DATA1',
           data: [2, 8, 3, 4, 5],
           backgroundColor: '#22242C'
        }, {
           label: 'DATA2',
           data: [1, 2, 3, 4, 5],
           backgroundColor: '#FFA755'
        }, {
           label: 'DATA3',
           data: [3, 1, 3, 4, 5],
           backgroundColor: '#B48DD3'
        }, {
           label: 'DATA4',
           data: [5, 2, 3, 4, 5],
           backgroundColor: '#6160DC'
        }, {
           label: 'DATA5',
           data: [2, 1, 3, 4, 5],
           backgroundColor: '#54C5EB'
        }, {
           label: 'DATA5',
           data: [1, 2, 3, 4, 5],
           backgroundColor: '#FF4A55'
        }],
        barPercentage: 0.5
     },
     plugins: [ChartDataLabels],
     options: {
      barPercentage: 0.5,
      plugins: {
          legend: {
              position: 'right',
              display: false,
          },
          datalabels: {
              anchor: 'center',
              align: 'center',
              color: 'white',        
              font: {
              weight: 'bold'
              },
              formatter: Math.round
          },
      },
      responsive: true,
      scales: {
        x: {
          stacked: true,
        },
        y: {
          stacked: true
        }
      }
     }
  };
  
  var stackedCtx = document.getElementById(&quot;stacked-1-canvas&quot;).getContext('2d');
  new Chart(stackedCtx, stackedConfig);
  </code></pre>
  <p>Even after putting anchor: 'center' in datalabels option, the labels are anchor at start. Even if I leave out the option, the default anchor should be center, but even then its anchored to the start position.</p>
  <p>Please help me sort this out.</p>