Enhance README with LightGBM Installation Guidance for Mac M1 Users (#1766)

* Update README.md

* Update README.md

* Update README.md

Author: xisen-w

README.md

@@ -172,6 +172,8 @@ Also, users can install the latest dev version ``Qlib`` by the source code accor
 
 **Tips**: If you fail to install `Qlib` or run the examples in your environment,  comparing your steps and the [CI workflow](.github/workflows/test_qlib_from_source.yml) may help you find the problem.
 
+**Tips for Mac**: If you are using Mac with M1, you might encounter issues in building the wheel for LightGBM, which is due to missing dependencies from OpenMP. To solve the problem, install openmp first with ``brew install libomp`` and then run ``pip install .`` to build it successfully. 
+
 ## Data Preparation
 Load and prepare data by running the following code: