Incompatibility with GitHub immutable releases

Currently, running the chart-releaser action with the following settings
```
with:
config: cr.yaml
version: v1.7.0
charts_dir: charts
mark_as_latest: true
packages_with_index: false
```

fails if immutable releases are enabled on the repository.
```
Error: error creating GitHub release 2.2.0: failed to upload release asset: /home/runner/work/secrets-store-csi-driver-provider-aws/secrets-store-csi-driver-provider-aws/.cr-release-packages/secrets-store-csi-driver-provider-aws-2.2.0.tgz: POST https://uploads.github.com/repos/aws/secrets-store-csi-driver-provider-aws/releases/282779817/assets?name=secrets-store-csi-driver-provider-aws-2.2.0.tgz: 422 Cannot upload assets to an immutable release. []
```

This is because asset uploads and release creation are performed in two separate steps. It is possible to create a release with artifacts attached to it in one step (at least through the GitHub UI) which should solve this problem.