title: can not set color in InstancedMesh in three.js 125 version
body: <p>I am trying in Three.js v-125 to randomly change the color of an instance of an instancedMesh as followed</p>
  <pre><code>    addSphere(){
  
          var geometry = new THREE.SphereGeometry(0.5, 32, 32);
          let material = new THREE.MeshBasicMaterial({ color: 0x8cde0d,});
          this.stars2 = new THREE.InstancedMesh(geometry, material,1000);
          let o3d = new THREE.Object3D();
          let position = new THREE.Vector3();
          let color = new THREE.Color();
          this.stars2.instanceMatrix.setUsage( THREE.DynamicDrawUsage ); 
  
          for (let i = 0; i &lt; 6000; i++) {
              const random = +(Math.random() * 10).toFixed(0);
              let colorValue = 0x8cde0d;           
              position.set(
                  Math.random() * 800 - 500,
                  Math.random() * 800 - 500,
                  Math.random() * 800 - 500
              )
              o3d.position.copy(position)
              o3d.updateMatrix()
              this.stars2.setMatrixAt(i++, o3d.matrix);
  
              //this.stars2.setColorAt(i, color.setHex( colorValue ));
              //this.stars2.setColorAt( i, color.setHex( 0xffffff * Math.random() ) );
                this.stars2.setColorAt( i, color.set(0xffffff * Math.random()));
  
          }
            this.stars2.instanceColor.needsUpdate = true;
            this.stars2.instanceMatrix.needsUpdate = true;
            this.scene.add(this.stars2);
  
      }
  </code></pre>
  <p>I tried three different ways</p>
  <pre><code>    this.stars2.setColorAt(i, color.setHex( colorValue ));
      this.stars2.setColorAt( i, color.setHex( 0xffffff * Math.random() ) );
      this.stars2.setColorAt( i, color.set(0xffffff * Math.random()));
  </code></pre>
  <p>but none of them works, kind of strange how to do it in the correct way</p>