ConnectorX 0.2.4

Bug Fix

• Fixing deallocating None bug #201
• Clickhouse support on new version #165
• Shrink array before return for arrow2 to reduce memory usage when result is small #196
• Fix Oracle port error #209

Others

• Improve Oracle performance by enlarging array size using prepared statement #127
• Upgrade arrow2 to 0.9 #221
• Add Postgres Json, TimestampTz support to arrow2 #235 #229
• Clean up python dependencies (remove ones for benchmarking)