feature: add type hint to event.py, row_event.py, binlogfilereader.py

Co-authored-by:    suhwan-cheon <[email protected]>
Co-authored-by:    ebang091 <[email protected]>
Co-authored-by:    yangbaechu <[email protected]>
Co-authored-by:    jaehyeonpy <[email protected]>

Author: 4 people