Report 0.42.1 in the macOS build config (#2836)

The 0.42.1 bump in #2835 updated `tauri.conf.json` and `version.rs` but
left `tauri-mac.conf.json` at 0.42.0, so the macOS release build would
report the wrong version.

- Sets `tauri-mac.conf.json` to 0.42.1.
- Extends
`package_identity_and_display_version_match_the_release_configuration`
to also check the macOS config. It fails before this change and passes
after; all 19 updater tests pass.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

<!-- coderabbit-ai-generated:v1 -->

## Summary by CodeRabbit

* **Chores**
  * Updated the macOS app version to 0.42.1.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

crates/desktop/artcraft/src/updates.rs

@@ -255,6 +255,8 @@ mod tests {
     let config: serde_json::Value = serde_json::from_str(include_str!("../tauri.conf.json")).expect("release configuration");
     assert_eq!(config["version"].as_str(), Some(ARTCRAFT_VERSION));
     assert_eq!(config["identifier"].as_str(), Some(APP.bundle_id().as_str()));
+    let mac: serde_json::Value = serde_json::from_str(include_str!("../tauri-mac.conf.json")).expect("macOS release configuration");
+    assert_eq!(mac["version"].as_str(), Some(ARTCRAFT_VERSION), "the macOS build must report the same version");
   }
 
   #[test]

crates/desktop/artcraft/tauri-mac.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2.0.0-rc",
   "productName": "ArtCraft",
-  "version": "0.42.0",
+  "version": "0.42.1",
   "identifier": "ai.artcraft.app",
   "build": {
     "frontendDist": "../../../frontend/apps/artcraft/dist",