chore: prepare 0.12.0 release (#25)

Cargo.toml

@@ -3,7 +3,7 @@ name = "tui-textarea-2"
 homepage = "https://github.com/srothgan/tui-textarea#readme"
 repository = "https://github.com/srothgan/tui-textarea"
 documentation = "https://docs.rs/tui-textarea-2/latest/tui_textarea/"
-version = "0.11.0"
+version = "0.12.0"
 edition = "2024"
 rust-version = "1.88.0" # for Ratatui 0.30 split crates
 authors = ["Simon Peter Rothgang <simonrothgang@icloud.com>", "rhysd <lin90162@yahoo.co.jp>"]