ci: add note, redirect errors

.github/workflows/functional-test.yml

@@ -35,6 +35,8 @@ jobs:
 
     runs-on: macos-14
 
+    # Please make sure the available Xcode versions and iOS versions
+    # on the runner images. /~https://github.com/actions/runner-images
     env:
       XCODE_VERSION: 15.3
       IOS_VERSION: 17.4
@@ -66,7 +68,7 @@ jobs:
         appium driver install xcuitest
         appium plugin install images
         appium plugin install execute-driver
-        nohup appium --use-plugins=images,execute-driver --relaxed-security --log-timestamp --log-no-colors --base-path=/wd/hub > appium.log &
+        nohup appium --use-plugins=images,execute-driver --relaxed-security --log-timestamp --log-no-colors --base-path=/wd/hub 2>&1 > appium.log &
 
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1