Remove transitive dependencies and update requirements

[foivospro]

As part of our ongoing research on Python dependency management, we identified that your project explicitly declares the dependency chardet, which is not directly used in the codebase but is installed transitively by higher-level packages such as okpy.

Keeping chardet in requirements.txt or setup.py unnecessarily locks its version and increases the risk of dependency conflicts, especially during upgrades. This cleanup removes chardet as a top-level requirement to let the resolver handle it based on the needs of the actual top-level packages.

This change aligns with the best practices recommended in the pip documentation, which encourages pruning unused or transitive dependencies to maintain a clean and maintainable dependency graph.