Upgrade Bundler version to 1.16.6
A few reasons for this change:
GitLab CE and Gitaly are now using bundler v1.16.6 to avoid https://github.com/bundler/bundler/issues/6537.
1.16.3 also ships with https://github.com/bundler/bundler/pull/6550, so we no longer need the patch for this.
Edited by GitLab Release Tools Bot