update iOS image

Author: ashwinimurt

.yamato/mobile-build-and-test.yml

@@ -46,7 +46,7 @@ build_{{ project.name }}_tests_{{ editor }}_iOS:
   name: Build {{ project.name }} Tests - {{ editor }} - iOS
   agent:
     type: Unity::VM::osx
-    image: mobile/macos-10.15-testing:stable
+    image: mobile/ios-macos-11:stable
     flavor: b1.large
   commands:
     - pip install unity-downloader-cli --index-url https://artifactory.prd.it.unity3d.com/artifactory/api/pypi/pypi/simple
@@ -81,7 +81,7 @@ run_{{ project.name }}_tests_{{ editor }}_iOS:
   agent:
       type: Unity::mobile::iPhone
       model: SE
-      image: mobile/macos-10.15-testing:stable
+      image: mobile/ios-macos-11:stable
       flavor: b1.medium
   # Set a dependency on the build job
   dependencies: