Publish iceberg-catalog-loader.

[blackmwk]

Is your feature request related to a problem or challenge?

1. Add iceberg-catalog-loader to publish workflow.
2. Update README.md for iceberg-catalog-loader.

Describe the solution you'd like

No response

Willingness to contribute

I can contribute to this feature independently

[kevinjqliu]

i see this is already published to crates.io https://crates.io/crates/iceberg-catalog-loader

[blackmwk]

I did it manually, but we need to add it to workflow.