Because the `git` module did not recognize SSH signed tags, those
signatures ended up in the `notes` column of the `release` table. While
future signatures will not end up there, Forgejo should clean up the old
ones.
This migration does just that: finds all releases that have an SSH
signature, and removes those signatures, preserving the rest of the
note (if any).
While this may seem like an expensive operation, it's only done once,
and even on the largest known Forgejo instance as of this
writing (Codeberg), the number of affected rows are just over a hundred,
a tiny amount all things considered.
Signed-off-by: Gergely Nagy <forgejo@gergo.csillger.hu>
