[FEATURE] CI - stop PR's where helm-docs hasn't run

**Is your feature request related to a problem? Please describe.**

Stop PR's where helm-docs hasn't run

**Describe the solution you'd like**

In PR CI, run helm-docs and fail if changes are detected.

**Describe alternatives you've considered**

Many headaches.

**Additional context**

Discussed on version-checker meeting 2024/08/15

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**Message from the maintainers**:

If you wish to see this enhancement implemented please add a 👍 reaction to this issue! We often sort issues this way to know what to prioritize.

Start by locating the repository's PR CI workflow and existing helm-docs configuration. Run helm-docs in CI, compare the generated files with the working tree, and make the check fail when changes are detected; done means a PR with ungenerated documentation is rejected.

索引モデルが issue の本文から書いたものです。