Add chart v1.5.0 link and update OWNERS

[saintube]

ChangeLogs:

1. Mark the v1.5.0 as the current chart.
2. Update approvers in the OWNERS.

Note on DCO:

If the DCO action in the integration test fails, one or more of your commits are not signed off. Please click on the Details link next to the DCO action for instructions on how to resolve this.

Checklist:

• I have bumped the chart version according to versioning
• I have updated the chart changelog with all the changes that come with this pull request according to changelog.
• Any new values are backwards compatible and/or have sensible default.
• I have signed off all my commits as required by DCO.

Changes are automatically published when merged to master. They are not published on branches.

[hormes]

/lgtm
/approve

[koordinator-bot]

[APPROVALNOTIFIER] This PR is APPROVED

Approval requirements bypassed by manually added approval.

This pull-request has been approved by: hormes

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

The pull request process is described 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