Remove python 3.8 support

### Feature Request / Improvement

Python version 3.8 is EOL on October 2024
https://devguide.python.org/versions/

We should remove support for it soon 
See comment https://github.com/apache/iceberg-python/pull/1068#discussion_r1719872522
