Update bundler to 2.3.6+
Goal
Update bundler to 2.3.6+ which ever includes https://github.com/rubygems/rubygems/pull/5291
Check https://rubygems.org/gems/bundler for release.
- GitLab and GitLab QA: !79251 (merged)
- GitLab Shell: gitlab-shell!554 (merged)
Background
We tried to upgrade bundler to 2.3.5 in !78298 (merged) to resolve gitlab-development-kit#1403 (closed) (it's got interfered by older bunlder 2.1.4), but it's reverted in !78419 (merged) due to https://github.com/rubygems/rubygems/issues/5290 and a fix is merged in https://github.com/rubygems/rubygems/pull/5291 where it's not released yet.
Edited by Lin Jen-Shin