Fix golang/appengine CI (#280)

With google-github-actions/setup-gcloud#539, they broke Github workflows specifying the "master" branch ahead of the rename of the branch to 'main'.

Author: bsiegert

.github/workflows/ci-v2.yaml

@@ -32,7 +32,7 @@ jobs:
  restore-keys: |
  ${{ runner.os }}-${{ matrix.go-version }}-go-
  - name: Set up Cloud SDK
- uses: google-github-actions/setup-gcloud@master
+ uses: google-github-actions/setup-gcloud@v0
  - name: Install
  working-directory: ${{env.working-directory}}
  env:

.github/workflows/ci.yml

@@ -30,7 +30,7 @@ jobs:
  restore-keys: |
  ${{ runner.os }}-${{ matrix.go-version }}-go-
  - name: Set up Cloud SDK
- uses: google-github-actions/setup-gcloud@master
+ uses: google-github-actions/setup-gcloud@v0
  - name: Install
  env:
  GO111MODULE: on