6106f223d2
The v6.x release line was missing from
packaging/appstream/org.cryptographic_triangles.TrianglesQt.metainfo.xml,
which means software centers (GNOME Software, KDE Discover, elementary
AppCenter, Flatpak, etc.) show the wallet as stuck at v5.3.7. bump-version.sh
flags this file as a manual follow-up; this commit closes that gap.
Skipped v6.1.2: that release was yanked (5c312bb published 2026-07-01,
superseded by 6.1.3) and the v6.1.3 changelog already documents the
replacement. Listing a yanked release would mislead users searching
for it.