Fix image values

[horjulf]

What this PR does / why we need it:

This fixes image tag template which is broken in 0.22.0.

at <.Values.image.tag>: can't evaluate field tag in type interface {}

Special notes for your reviewer:

Checklist

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• [x] Chart Version bumped
• [x] Changes are documented in the README.md

[rimusz]

Thank you for the PR 👍