Release 0.2.2

Unit test: expected output columns without namespace prefix

The 0.2.1 install check failed with bad.column.names -- ds0.filename;
the operator's PNG relation has plain filename/mimetype/.content.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

0.1.0

add min  and max dot size as property

0.0.1

Update README.md