剔除node-sass改用sass3.0，修复部分sass3.0兼容警告

src/views/app/app.vue

@@ -623,7 +623,7 @@ export default {
 </script>
 
 <style scoped>
-/deep/ .file-box .el-upload {
+::v-deep .file-box .el-upload {
   width: 100%;
   height: 100%;
   box-sizing: border-box;
@@ -632,7 +632,7 @@ export default {
   justify-content: center;
   align-items: center;
 }
-/deep/ .avatar-uploader {
+::v-deep .avatar-uploader {
   width: 100%;
   box-sizing: border-box;
   height: 100%;