Merge branch 'sh-allow-hashie-mash-serialize' into 'master'

Allow loading of Hashie::Mash in YAML

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/143694



Merged-by: drew stachon <730684-drew@users.noreply.gitlab.com>
Approved-by: drew stachon <730684-drew@users.noreply.gitlab.com>
Co-authored-by: Stan Hu <stanhu@gmail.com>