Upgrade gitlab-workhorse to v8.17.0

Full list of changes: https://gitlab.com/gitlab-org/gitlab-workhorse/blob/master/CHANGELOG v8.16.0 was shipped with the Cloud Native Helm Charts since 12.5, so it's best that we get in sync.

Upgrade gitlab-workhorse to v8.17.0
2cebd6da · Stan Hu · fac7279f · 2cebd6da
Commit 2cebd6da authored 5 years ago by Stan Hu
--- a/GITLAB_WORKHORSE_VERSION
+++ b/GITLAB_WORKHORSE_VERSION
-8.14.1
+8.17.0