[Core] Fix iOS 12 spec lint failure from incomplete FirebaseCoreInternal implementation

[ncooke3]

Skipping the version bump in FirebaseCoreExtension.podspec because the changed .m file is not listed in that spec's sources.

[paulb777]

Also, probably worth touching Gemfile and making sure everything else builds ok

[paulb777]

Thanks for the thorough fix!

[ncooke3]

Green CI on this PR. Merging and will create CocoaPods-11.4.2 tag at tip of release-11.4 branch.

[ncooke3]

Global CI running in #13955

[ncooke3]

Tag created: https://github.com/firebase/firebase-ios-sdk/releases/tag/CocoaPods-11.4.2

Staging to SpecsStaging

[ncooke3]

FirebaseCore 11.4.0 will float to pick up the new FirebaseCoreInternal 11.4.2. I confirmed this in an app with the following Podfile:

source 'https://github.com/firebase/SpecsStaging.git'
source 'https://cdn.cocoapods.org/'

platform :ios, '13.0'

target 'FlutterIssue' do
  # Comment the next line if you don't want to use dynamic frameworks
  use_frameworks!

  # Pods for FlutterIssue
  pod 'FirebaseAuth', '11.4.0'
  
  target 'FlutterIssueTests' do
    inherit! :search_paths
    # Pods for testing
  end

  target 'FlutterIssueUITests' do
    # Pods for testing
  end

end

While a public API in FirebaseCoreInternal changed, the signature matches the completion handler API used by FirebaseCore. Since there should be no other usage of the API, this shouldn't cause issue.

[paulb777]

For completeness, would you also test adding pod 'FirebaseCore', '11.4.0' to the Podfile.

[ncooke3]

Done. Looks good. Podfile.lock:

PODS:
  - FirebaseCore (11.4.0):
    - FirebaseCoreInternal (~> 11.0)
    - GoogleUtilities/Environment (~> 8.0)
    - GoogleUtilities/Logger (~> 8.0)
  - FirebaseCoreInternal (11.4.2):
    - "GoogleUtilities/NSData+zlib (~> 8.0)"
  - GoogleUtilities/Environment (8.0.2):
    - GoogleUtilities/Privacy
  - GoogleUtilities/Logger (8.0.2):
    - GoogleUtilities/Environment
    - GoogleUtilities/Privacy
  - "GoogleUtilities/NSData+zlib (8.0.2)":
    - GoogleUtilities/Privacy
  - GoogleUtilities/Privacy (8.0.2)

DEPENDENCIES:
  - FirebaseCore (= 11.4.0)

SPEC REPOS:
  https://github.com/firebase/SpecsStaging.git:
    - FirebaseCoreInternal
  trunk:
    - FirebaseCore
    - GoogleUtilities

SPEC CHECKSUMS:
  FirebaseCore: e0510f1523bc0eb21653cac00792e1e2bd6f1771
  FirebaseCoreInternal: 35731192cab10797b88411be84940d2beb33a238
  GoogleUtilities: 26a3abef001b6533cf678d3eb38fd3f614b7872d

PODFILE CHECKSUM: 3676495040c7d08dcf76b3612ae88622969a1669

COCOAPODS: 1.15.2