Image assets no longer being published with gem

While building the gem, the image assets are supposed to be copied into app/assets/images/tanuki_emoji, which are then packages with the gem.

Version 0.6.0 of the gem includes these assets, however any following gems do not. I believe this was caused by Automate generation of releases and changelogs (!48 - closed), which started using a component file '/ci/gem-release.yml'