Update rubik conversion docs with Ultralytics version warning

[samfreund]

Meta

Merge checklist:

• [x] Pull Request title is short, imperative summary of proposed changes
• [x] The description documents the what and why
• [ ] If this PR changes behavior or adds a feature, user documentation is updated
• [ ] If this PR touches photon-serde, all messages have been regenerated and hashes have not changed unexpectedly
• [ ] If this PR touches configuration, this is backwards compatible with settings back to v2025.3.2
• [ ] If this PR touches pipeline settings or anything related to data exchange, the frontend typing is updated
• [ ] If this PR addresses a bug, a regression test for it is added

[samfreund]

Sounds like there should be an update pushed to AIhub on the 29th. I'm going to wait until then, and recommend pinning to whatever version that happens to be.

[samfreund]

Don't merge yet, I wanna test that this actually works.

[katzuv]

Don't merge yet, I wanna test that this actually works.

You can also mark the PR as work in progress.