chore: update dependencies

[reneleonhardt]

What kind of change does this PR introduce?

Chores

• Update cargo dependencies, docker, github-actions and mermaid
• Let dependabot update cargo, docker and github-actions (pip contains no version constraints)
• Add Postgres 18
• Add Rust stable to the CI matrix to catch upcoming problems
• Pin digests in github-actions to improve security

What is the current behavior?

Please link any relevant issues here.

What is the new behavior?

Feel free to include screenshots if it includes visual changes.

Additional context

Not Updated

• arrow 57 because iceberg hasn't released their updates yet
• const-oid 0.10 because the security ecosystem hasn't released their updates yet
• lakekeeper-postgres should always be the latest for all postgres versions 14 - 18 in docker-compose.yaml?

[iambriccardo]

Did you run any tests for this PR?

Asking since I wanted to know the rationale behind some of the version changes and if you made sure there were no breaking changes.

[iambriccardo]

Also, as a follow up, could you explain the rationale behind updating Postgres to 18? The pipeline should support it but it requires proper testing.