fix(FileInput): 隐藏原生input file提示文字 #700 (#701)

Author: nullptr-z

packages/react-file-input/src/style/index.less

@@ -5,7 +5,7 @@
     &::-webkit-file-upload-button {
       background: transparent;
       border: 0;
-      color: red;
+      color: #0000;
       position: absolute;
       left: -300px;
     }