The extension's version-bump section names the version mix.exs holds,
and says in its own text that a release bead updates that line with it.
This is that release bead, so the line moves to 0.3.2.

It keeps 0.3.1 visible as the last version actually on Hex: the prep is
merged-pending-publish until the operator tags and publishes.

Refs: sob-0h3