Update dependency nokogiri to '~> 1.15', '>= 1.15.3'

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/125325



Merged-by: Alex Pooley <apooley@gitlab.com>
Approved-by: Costel Maxim <cmaxim@gitlab.com>
Approved-by: Alex Pooley <apooley@gitlab.com>
Co-authored-by: Brett Walker <bwalker@gitlab.com>
Co-authored-by: Lin Jen-Shin <jen-shin@gitlab.com>