v0.1.0a6

0.1.0a6: the documented --credential-file becomes a thing you can run (#14)

docs/connecting-a-project.md shows hullwork projects add --credential-file, and the image those
documents pin — 0.1.0a5 — answers unrecognized arguments. Item 163's fix landed after that
release, so the sentence was true of main and false of the artefact anybody actually pulls.

This bumps the five places that name a version. What it releases: --credential-file for
projects add and rotate-secret, which takes the only high code-scanning alert — a credential
with nowhere to go but standard output — and gives it a mode-600 file instead; plus items 162 and
164, which closed the rest of the alerts.

Signed-off-by: Javier Miralles Rancaño 68760931+FlagshipDev@users.noreply.github.com