Bug: Stable release becomes outdated very quickly due to hard coding

### What happened?

You appear to set a `stableHelmVersion` in `run.ts`. That's problematic because the stable version changes frequently so this action quickly ends up with an outdated stable version.

https://github.com/Azure/setup-helm/blob/df342a2656c018d52484e7d07ce33e4ade6254bb/src/run.ts#L13

Currently, the "stable" version points at 3.13.3 which has not been the latest stable for 1.5 years (since January 2024): https://github.com/helm/helm/releases/tag/v3.14.0

You should probably call it `defaultHelmVersion` as stable is misleading.

Also, this version should be updated with every release to not have too much of a gap between actual upstream stable and this action's "stable".

Using old versions means that newly introduced syntax will not work, e.g. `--skip-schema-validation`, see #187

### Version

- [x] I am using the latest version

### Runner

default

### Relevant log output

NA