Publish fiftyone_pipeline_derivedproperty once its first release is agreed #154

The draft #125 adds the package fiftyone_pipeline_derivedproperty with "Publish": false and no FirstVersion in ci/packages.json, so Publish does not release it. Nothing yet says when it is first released.

A new project on PyPI has its page marked noindex for search engines for its first 30 days, so the first release starts that wait.

What to do, once the first release is agreed: give the package a FirstVersion and "Publish": true in ci/packages.json, check with a Publish dry run that it is released at that version and that nothing else moves, and say in that release's notes how to add the element.