perf[style]: use webpack alias instead of hard code src path (#1338)

src/components/Upload/singleImage3.vue

@@ -83,7 +83,7 @@ export default {
 </script>
 
 <style rel="stylesheet/scss" lang="scss" scoped>
-@import "src/styles/mixin.scss";
+@import "~@/styles/mixin.scss";
 .upload-container {
   width: 100%;
   position: relative;