Update ReadMe.md

ReadMe.md

@@ -27,7 +27,10 @@ You can also build PolyFit from the source code:
 
 * Clone the repository or download the [source code](https://github.com/LiangliangNan/PolyFit).
 * Dependencies
-  - [Qt5](https://www.qt.io/) (v5.12.12, v5.10.1, v5.9.2, and v5.8.0 were tested). Qt is required by the [GUI demo](./code/PolyFit). You should still be able to build the [command-line example](./Example) without Qt. 
+  - [Qt5 or Qt6](https://www.qt.io/download-qt-installer-oss) ([v5.14.2](https://download.qt.io/archive/qt/5.14/5.14.2/), 
+    [v5.12.12](https://download.qt.io/archive/qt/5.12/5.12.12/), [v6.7.3](https://www.qt.io/download-qt-installer-oss) 
+    have been tested). Qt is required by the [GUI demo](./code/PolyFit). You should still be able to build 
+    the [command-line example](./Example) without Qt. 
   - [CGAL](http://www.cgal.org/index.html) (v6.0, v5.5, v5.0, v4.11.1, and v4.10 were tested).
 
 * Build PolyFit