Add error handling and ensure keychain is deleted

fastlane/Fastfile

@@ -140,28 +140,33 @@ platform :ios do
     use_build_sdk = !ENV['BUILD_SDK'].empty?
     use_build_destination = !ENV['BUILD_DESTINATION'].empty?
     use_cloned_source_packages_path = !ENV['CLONED_SOURCE_PACKAGES_PATH'].empty?
-    build_app(
-      workspace: use_workspace ? ENV['WORKSPACE_PATH'] : nil,
-      project: !use_workspace ? ENV['PROJECT_PATH'] : nil,
-      configuration: ENV['CONFIGURATION'],
-      scheme: ENV['SCHEME'],
-      output_directory: File.dirname(ENV['OUTPUT_PATH']),
-      output_name: File.basename(ENV['OUTPUT_PATH']),
-      clean: true,
-      cloned_source_packages_path:
-        if use_cloned_source_packages_path
-          ENV['CLONED_SOURCE_PACKAGES_PATH']
-        else
-          nil
-        end,
-      export_method: ENV['EXPORT_METHOD'],
-      export_options: use_export_options ? ENV['EXPORT_OPTIONS'] : nil,
-      skip_profile_detection: use_export_options,
-      sdk: use_build_sdk ? ENV['BUILD_SDK'] : nil,
-      destination: use_build_destination ? ENV['BUILD_DESTINATION'] : nil
-    )
-
-    delete_keychain(name: 'ios-build.keychain')
+    begin
+      build_app(
+        workspace: use_workspace ? ENV['WORKSPACE_PATH'] : nil,
+        project: !use_workspace ? ENV['PROJECT_PATH'] : nil,
+        configuration: ENV['CONFIGURATION'],
+        scheme: ENV['SCHEME'],
+        output_directory: File.dirname(ENV['OUTPUT_PATH']),
+        output_name: File.basename(ENV['OUTPUT_PATH']),
+        clean: true,
+        cloned_source_packages_path:
+          if use_cloned_source_packages_path
+            ENV['CLONED_SOURCE_PACKAGES_PATH']
+          else
+            nil
+          end,
+        export_method: ENV['EXPORT_METHOD'],
+        export_options: use_export_options ? ENV['EXPORT_OPTIONS'] : nil,
+        skip_profile_detection: use_export_options,
+        sdk: use_build_sdk ? ENV['BUILD_SDK'] : nil,
+        destination: use_build_destination ? ENV['BUILD_DESTINATION'] : nil
+      )
+          item1 # This causes an error
+    rescue => ex
+      UI.error(ex)
+    ensure
+      delete_keychain(name: 'ios-build.keychain')
+    end
   end
 
   # https://github.com/CocoaPods/Xcodeproj/issues/505#issuecomment-584699008