ios: ensure the git tree is clean when / after building

ios/fastlane/Fastfile

 platform :ios do
   desc "Push a new beta build to TestFlight"
   lane :deploy do
+    # Make sure we are on a clean tree
+    ensure_git_status_clean
+
     # Set the app identifier
     update_app_identifier(
       xcodeproj: "app/app.xcodeproj",
 
     # Cleanup
     clean_build_artifacts
+    reset_git_repo(skip_clean: true)
   end
 end