Fix Volumetric import

src/PostProcesses/volumetricLightScatteringPostProcess.ts

@@ -21,6 +21,7 @@ import "../Meshes/Builders/planeBuilder";
 
 import "../Shaders/depth.vertex";
 import "../Shaders/volumetricLightScattering.fragment";
+import "../Shaders/volumetricLightScatteringPass.vertex";
 import "../Shaders/volumetricLightScatteringPass.fragment";
 import { Color4, Color3 } from '../Maths/math.color';
 import { Viewport } from '../Maths/math.viewport';