Update dependency discordrb-webhooks to '~> 3.5'

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/145577



Merged-by: Luke Duncalfe <lduncalfe@gitlab.com>
Approved-by: Luke Duncalfe <lduncalfe@gitlab.com>
Approved-by: Greg Myers <gmyers@gitlab.com>
Reviewed-by: Greg Myers <gmyers@gitlab.com>
Co-authored-by: GitLab Renovate Bot <gitlab-bot@gitlab.com>