chore(release): bump version to 1.2.12

Hotfix release. Reverts titlebar-mode-selector and PR #406 (broken
window chrome on Linux); preserves PR #407 (sticky home header) and
adds PR #408 (macOS native icon and tray variants by @Vudgekek).

cc

src-tauri/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "qbz-nix"
-version = "1.2.11"
+version = "1.2.12"
 description = "Native high-fidelity client for Qobuz™ subscribers on Linux with Hi-Fi audio support (uses the Qobuz API; not certified by Qobuz)"
 authors = ["blitzkriegfc"]
 edition = "2021"