fix(deps): update rust crate gtk to 0.18

Author: renovate[bot]

src-tauri/Cargo.toml

@@ -38,7 +38,7 @@ fix-path-env = { git = "https://github.com/tauri-apps/fix-path-env-rs" }
 native-dialog = "0.7.0"
 
 [target.'cfg(target_os = "linux")'.dependencies]
-gtk = "0.15"
+gtk = "0.18"
 webkit2gtk = "0.18" # if tauri build fails, make sure to match this version to what we have in tauri
 dialog = "0.3.0"