Use chart-releaser-action tag v1.6.0

Context: https://github.com/matrix-org/dendrite/pull/3427#issuecomment-2359139622 Try tagged version of chart-releaser-action now that mark_latest option is available ### Pull Request Checklist <!-- Please read https://matrix-org.github.io/dendrite/development/contributing before submitting your pull request --> * [x] I have added Go unit tests or [Complement integration tests](https://github.com/matrix-org/complement) for this PR _or_ I have justified why this PR doesn't need tests * [x] Pull request includes a [sign off below using a legally identifiable name](https://matrix-org.github.io/dendrite/development/contributing#sign-off) _or_ I have already signed off privately Signed-off-by: `Rhea Danzey <rdanzey@element.io>`