Bazel ios example is failing at Bazel@HEAD in downstream CI

[sgowroji]

https://buildkite.com/bazel/bazel-at-head-plus-downstream/builds/2997#0187e486-4407-4dd3-b26b-2b14c15c9513

Platform : Bazel Examples (tutorials (Bazel end-to-end example) on :mac: (OpenJDK 11, Xcode))

 ERROR: /Users/buildkite/builds/bk-imacpro-14/bazel-downstream-projects/examples/tutorial/ios-app/BUILD:19:16: in ios_application rule //ios-app:ios-app:
--
  | Traceback (most recent call last):
  | File "/private/var/tmp/_bazel_buildkite/b49fc1f9c5a865d3b96f0ff3908db6a2/external/build_bazel_rules_apple/apple/internal/ios_rules.bzl", line 187, column 66, in _ios_application_impl
  | debug_outputs = linking_support.debug_outputs_by_architecture(link_result.outputs)
  | File "/private/var/tmp/_bazel_buildkite/b49fc1f9c5a865d3b96f0ff3908db6a2/external/build_bazel_rules_apple/apple/internal/linking_support.bzl", line 45, column 68, in _debug_outputs_by_architecture
  | bitcode_symbol_maps[link_output.architecture] = link_output.bitcode_symbols
  | Error: 'apple_linking_output' value has no field or method 'bitcode_symbols'
  | Available attributes: architecture, binary, dsym_binary, environment, linkmap, platform
  | (06:06:24) ERROR: /Users/buildkite/builds/bk-imacpro-14/bazel-downstream-projects/examples/tutorial/ios-app/BUILD:19:16: Analysis of target '//ios-app:ios-app' failed
  | (06:06:24) ERROR: Analysis of target '//ios-app:ios-app' failed; build aborted:
ERROR: Analysis of target '//ios-app:ios-app' failed; build aborted: 

Steps followed :

1. git clone https://github.com/bazelbuild/examples.git
2. git reset c1d0fcc --hard
3. export USE_BAZEL_VERSION=8087520b153832656695fef6f3654ed432642c98
4. cd examples/tutorial/ios-app
5. bazel build //ios-app

CC @meteorcloudy

[meteorcloudy]

rules_apple needs to be fixed and updated first.
bazelbuild/rules_apple#1956

[keith]

#289