Uncomment and reenable using local GoogleSignIn.podspec in unit_tests.yml

[mdmathias]

Context

#399 reverted GoogleSignInSwiftSupport.podspec's dependency on the GoogleSignIn pod to be 7.1+. This meant that the dependency for GSI in GoogleSignInSwiftSupport in the fac-eap branch did not match the version listed in GoogleSignIn.podspec, which was "7.1.0-fac-beta-1.1.0".

Problem

This mismatch, seemingly innocuous, led to pod lib lint failures (locally and PR runs) due to a version mismatch. Ultimately, the issue is that the pod lib lint command passed in the local GoogleSignIn.podspec, but linting GoogleSignInSwiftSupport.podspec would fail since the latter was looking for version 7.1+, and GoogleSignIn.podspec listed version "7.1.0-fac-beta-1.1.0".

To Do

#399 resolved the issue by updating unit_tests.yml to not use the local GoogleSignIn.podspec. This transformed the failing command:

pod lib lint GoogleSignInSwiftSupport.podspec --verbose \
  --sources=https://cdn.cocoapods.org/ \
  --include-podspecs='GoogleSignIn.podspec'

to this passing version:

pod lib lint GoogleSignInSwiftSupport.podspec --verbose \
  --sources=https://cdn.cocoapods.org/ \

When we merge fac-eap to the main branch, we should reenable using the local podspec. We should also make sure that the version of GSI listed in GoogleSignInSwiftSupport.podspec matches the version in GoogleSignIn.podspec.

[mdmathias]

In particular, the pod-lib-lint job needs to look like this again:

  pod-lib-lint:
    runs-on: ${{ matrix.os }}
    strategy:
      fail-fast: false
      matrix:
        os: [macos-12]
        podspec: [GoogleSignIn.podspec, GoogleSignInSwiftSupport.podspec]
        flag: [
          "",
          "--use-static-frameworks"
        ]
        include:
          - podspec: GoogleSignInSwiftSupport.podspec
            includePodspecFlag: "--include-podspecs='GoogleSignIn.podspec'"
    steps:
    - uses: actions/checkout@v3
    - name: Update Bundler
      run: bundle update --bundler
    - name: Install Ruby gems with Bundler
      run: bundle install
    - name: Lint podspec using local source
      run: |
        pod lib lint ${{ matrix.podspec }} --verbose \
           ${{ matrix.includePodspecFlag }} ${{ matrix.flag }}