message: Install the deps using yarn --frozen-lockfile.
  This change ensures that yarn will not generate a lockfile.
diff: @@ -49,7 +49,7 @@ jobs:
  with:
  node-version: ${{ matrix.node_version }}
  - name: Install dependencies
  - run: yarn
  + run: yarn --frozen-lockfile
  - name: Disable hard-source-webpack-plugin
  run: echo "::set-env name=HARP_NO_HARD_SOURCE_CACHE::true"
  - name: Pretest
  @@ -86,7 +86,7 @@ jobs:
  - name: Tests on Chrome (Linux)
  run: |
  set -ex
  - yarn
  + yarn --frozen-lockfile
  google-chrome --version
  whereis google-chrome
  yarn test-browser --headless-chrome --timeout ${{ env.browserTestTimeout }}
  