[Feature Request] Allow custom yamllint rules

Context:

My workflow keep failling with: `[comments] too few spaces before comment`

I'm using vscode as editor. And I've tried 3 different yaml formatter plugings to format the values file
- YAML
- Prettier
- Better-YAML

All of them does not add 2 space before # comments, nor support configuring that.
Yamllint does support customizing that, ct also does.
But chart-testing-action does not support that.

So please consider adding this feature.

If you maintainers think that's OK, I can make a PR if you don't have spare time. 😃

link:
- https://github.com/redhat-developer/vscode-yaml/issues/433
- https://github.com/prettier/prettier/issues/6780