fix: export model-ply.(#22)

Author: hujiulong

src/index.js

@@ -3,6 +3,7 @@ import Vue from 'vue'
 import ModelObj from './model-obj.vue'
 import ModelThree from './model-three.vue'
 import ModelStl from './model-stl.vue'
+import ModelPly from './model-ply.vue'
 import ModelCollada from './model-collada.vue'
 import ModelGltf from './model-gltf.vue'
 
@@ -20,6 +21,7 @@ const components = [
     ModelThree,
     ModelJson,
     ModelStl,
+    ModelPly,
     ModelCollada,
     ModelDae,
     ModelGltf,
@@ -41,6 +43,7 @@ export {
     ModelThree,
     ModelJson,
     ModelStl,
+    ModelPly,
     ModelCollada,
     ModelDae,
     ModelGltf,