LogDrop Taint v1.23.0

LogDrop Taint 1.23.0 — rotate the suppressions signing key

The private half of the previous pair was printed to a terminal while verifying
the dev deploy. It never left that machine, never entered git and reached no
third party — but this key exists so that what it signs cannot be forged, and
that property is not something to reason about after the fact.

Rotated instead. The old key is worthless from this release on.

Done now because the cost is currently zero: the feature shipped yesterday and no
signed suppression file exists anywhere. The same rotation in six months would
invalidate every file in every customer repository.

The licence key pair is untouched. Different pair, never exposed, and every
licence already issued keeps working.