Enable Github's `Immutable releases`

[Slamdunk]

https://docs.github.com/en/code-security/supply-chain-security/understanding-your-software-supply-chain/immutable-releases

[hslatman]

Hey @Slamdunk, thank you for opening the issue.

The setting has been enabled on this repo, and the next release will be subject to it.

[hslatman]

Briefly reopening for now to make sure things are OK, and to be able to keep tabs on it.

EDIT: the setting was temporarily disabled after the RC release test to make sure the release could go out in time. We'll have it enabled for the next release.

[Slamdunk]

https://github.com/smallstep/cli/releases/tag/v0.30.4 has not been released as Immutable

[Slamdunk]

But https://github.com/smallstep/cli/releases/tag/v0.30.3-rc1 has been 🤔

[hslatman]

Yes, that was a test. v0.30.4 was released without to ensure it would go out. There was an issue in CI before. The next release should have it, hence why I reopened.