release: prepare Nebula Terminal 1.3.1

nebula_split/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "nebula-split"
-version = "1.3.0"
+version = "1.3.1"
 license = "GPL-3.0-or-later"
 description = "Shared split-pane rules: layout tree, geometry, divider drag and directional focus"
 publish = false