Log Message:
graphics/ruby-chunky_png: update to 1.3.10

=== 1.3.10 - 2018-01-23

- Fixed a regression in Datastream#metadata, which was not able to deal with \ 
iTXt chunks.

=== 1.3.9 - 2018-01-23

- Add support for reading and writing an international textual data (iTXt chunks).