Bug: Support Bazel 6 --incompatible_unambiguous_label_stringification

[erikkerber]

Describe the bug

Generating BwX with Bazel 6 may result in the error similar to:

ERROR: Internal precondition failure:
Target //App:Slack was not found in the transitive dependencies of @//App:Slack-BwX.generator's `top_level_targets` attribute. Did you reference an alias (only actual target labels are supported in Scheme definitions)? Check that //App:Slack is spelled correctly, and if it is, add it or a target that depends on it to @//App:Slack-BwX.generator's `top_level_targets` attribute.
Please file a bug report at https://github.com/buildbuddy-io/rules_xcodeproj/issues/new?template=bug.md

Setting --noincompatible_unambiguous_label_stringification can help project generation, but it may fail on repos that relied on referencing its own workspace name, such as those who use the provisioning_profile_repository rule:

bazelbuild/bazel#15916

Reproduction steps

Generate a BwX project in Bazel 6 (6.0.0-pre.20220922.1)

Expected behavior

Versions

• Bazel: 6.0.0-pre.20220922.1
• rules_xcodeproj: 0.8+ (df3fc20173e24df2f981104e81594008053c97bd53171b34269cb71cee6fbd25)
• rules_apple: 1.1.2
• rules_swift: 1.2.0

Additional context