UpgradeTracker: use List<String> as HashMap key instead of String[]

[abrbird]

https://github.com/kserve/modelmesh/issues/143

[oss-prow-bot[bot]]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: abrbird Once this PR has been reviewed and has the lgtm label, please assign rafvasq for approval by writing /assign @rafvasq in a comment. For more information see:The Kubernetes Code Review Process.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment Approvers can cancel approval by writing /approve cancel in a comment