devel/rubygem-ipynbdiff: update to 0.4.7

Required for gitlab-ce 15.0.0.
Changelog:
https://gitlab.com/gitlab-org/incubation-engineering/mlops/rb-ipynbdiff/-/tags

0.4.7
Adds options to hide embedded images

0.4.6
Fixes issue when png outputs can have multiple lines