* Drop support for Python2.7 and Python3.5.
* Suport for Python3.8 and Python3.9.
* Add type hints.
* Update JDBC driver to 2.0.15.
The download URL for the JDBC driver has changed since 2.0.15.
2.0.14: https://s3.amazonaws.com/athena-downloads/drivers/JDBC/SimbaAthenaJDBC_2.0.14/AthenaJDBC42_2.0.14.jar
2.0.15: https://s3.amazonaws.com/athena-downloads/drivers/JDBC/SimbaAthenaJDBC-2.0.15.1000/AthenaJDBC42.jar
* Redesign Formatter and Converter classes.
Add JDBCTypeConverter abstract class and Formatter abstract class.
Change the name of JDBCTypeConverter to DefaultJDBCTypeConverter.
Change the name of ParameterFormatter to DefaultParameterFormatter.