bundler gem has been included in the Docker official Ruby image since 2.1.
Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

Fix #55740:  Use the '--no-document' option instead of the 'gem' tool's deprecated options

Closes #55740

See merge request gitlab-org/gitlab-ce!24049

Fix commit SHA not showing in merge request compare dropdown

Closes #55822

See merge request gitlab-org/gitlab-ce!24084

Upgrade Omniauth and JWT gems to switch away from Google+ API

Closes #55668

See merge request gitlab-org/gitlab-ce!24068

`--no-rdoc` and `--no-ri` have been deprecated since RubyGems 2.0:
https://github.com/rubygems/rubygems/blob/v2.0.0/History.txt#L43

They were finally removed in a recent release:
https://github.com/rubygems/rubygems/pull/2354