Fix Deprecated Usage of `np.int` in `to_cstyle` Function in `gen_config.py`

[kanndil]

Description: This pull request addresses the deprecated usage of np.int in the to_cstyle function within the gen_config.py script. The np.int usage has been replaced with np.int32 to resolve the issue. The changes have been tested locally and verified to resolve the deprecated usage warning.

Changes Made:

• Replaced np.int with np.int32 in the to_cstyle function

Testing:

• Tested the to_cstyle function with various input data to ensure correct behavior
• Verified that the deprecated usage warning no longer appears

Related Issue: Fixes #212

[majianjia]

Looks superb. Thank you very much