Force http/1.1 for readiness proxy_pass

[ToshieUya]

PR Checklist

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

• [x] Chart Version bumped
• [x] Chart packaged and index updated (you can use ./release)
• [x] CHANGELOG.md updated
• [x] Variables and other changes are documented in the README.md

What this PR does / why we need it: Force HTTP/1.1 to istio readiness proxy_pass

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes # No tickets but I'm getting 426 error on readiness request from istio. Have to force HTTP/1.1 for the readiness check request.

Special notes for your reviewer:

[chrisvfabio]

I'm running into the same issue with istio. Is there any update on when this is getting merged?

Thanks!