Set GitLab 14.0 as the min supported upgrade version

What does this MR do?

To upgrade accross major versions users must:

• Upgrade to the latest patch of 13.12
• Upgrade to the latest patch of 14.0 while followin the upgrade docs for that version
• Upgrade further into 14.x following normal upgrade procedures

https://docs.gitlab.com/ee/update/index.html#upgrading-to-a-new-major-version

Test plan

(Note that the check does not run for non-semver versions)

1. Install a previous release version of the chart 4.12.x.
2. Check this branch, and modify your top-level Chart.yml file to be semver values
   • appVersion should be 14.1.0
   • version should be 5.1.0
3. Attempt to upgrade to the local version
   • The upgrade should fail, and the upgrade status pod termination message should have the expected reason
4. Upgrade to the release version of 5.0 following https://gitlab.com/gitlab-org/charts/gitlab/-/blob/master/doc/installation/upgrade.md#upgrade-steps-for-50-release
   • This should succeed
5. Attempt the update to the local version again
   • This should now succeed

diff --git a/Chart.yaml b/Chart.yaml
index d231228ba..6b91b4bee 100644
--- a/Chart.yaml
+++ b/Chart.yaml
@@ -1,8 +1,8 @@
 ---
 apiVersion: v1
 name: gitlab
-version: 5.0.5
-appVersion: master
+version: 5.1.0
+appVersion: 14.1.0
 description: Web-based Git-repository manager with wiki and issue-tracking features.
 keywords:
 - gitlab

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion.

Required

• Merge Request Title and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
• Documentation created/updated
• Tests added
• Integration tests added to GitLab QA
• Equivalent MR/issue for omnibus-gitlab opened