Enable yamllint for Helm Chart and GitHub Actions

[lucacome]

Proposed changes

Problem: We're not linting YAML files in the Helm Chart and GitHub Actions directories

Solution: Enable yamllint for these directories and fix the problems.

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

Release notes

If this PR introduces a change that affects users and needs to be mentioned in the release notes,
please add a brief note that summarizes the change.

NONE

[sjberman]

Does helm lint do anything different from yamllint? Do we want to add that as well? (maybe separate PR)

[lucacome]

Does helm lint do anything different from yamllint? Do we want to add that as well? (maybe separate PR)

We already have helm lint in the lint workflow, but it doesn't lint the values.yaml. I'm working on adding some things to that workflow soon, that's how I stumbled into this and decided to open a separate PR 🙂