Lint values files in ci directory

[jlegrone]

What this PR does / why we need it:

What it says on the tin. 😄I figure it would be best to lint all the values files we know about.

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

Special notes for your reviewer:

This introduces 9 new errors for the stable charts:

$ ct lint --chart-dirs=stable --all | grep ✖︎
 ✖︎ stable/ethereum > Error waiting for process: exit status 1
 ✖︎ stable/keycloak > Error waiting for process: exit status 1
 ✖︎ stable/kibana > Error waiting for process: exit status 1
 ✖︎ stable/metrics-server > Error waiting for process: exit status 1
 ✖︎ stable/minecraft > Error waiting for process: exit status 1
 ✖︎ stable/mission-control > Error waiting for process: exit status 1
 ✖︎ stable/prometheus-operator > Error waiting for process: exit status 1
 ✖︎ stable/sumologic-fluentd > Error waiting for process: exit status 1
 ✖︎ stable/xray > Error waiting for process: exit status 1

[jlegrone]

/assign @unguiculus