v0.5.4

Say so when the published version predates the fix

The notebook installs from PyPI, PyPI is still on 0.5.3, and the timeout
that ends the eternal spinner is in 0.5.4 — which was never tagged, so it
was never published. Running the notebook fetched code that still has the
unbounded read. Nothing had changed because nothing could have.

The setup cell now knows which version the notebook needs and says when
what it got is older, along with the command to install from main. Before
this it printed "library-hiroba 0.5.3" and left the reader to work out
that 0.5.3 was the problem — which is not something a reader can know.

Checked against the five states this cell can find itself in: published
version too old, current, stale copy still in memory, second run in one
session, and PyHiroba, where a vendored copy has no metadata to compare.