title: Why does this github workflow fail when trying to yarn install this dependency?
body: <p>So I have a forked repo with a github workflow setup, which fails when trying to yarn install a dependency due to permission rights:</p>
  <pre><code>Run yarn install
  yarn install v1.22.10
  [1/4] Resolving packages...
  [2/4] Fetching packages...
  error Command failed.
  info Visit https://yarnpkg.com/en/docs/cli/install for documentation about this command.
  Exit code: 128
  Command: git
  Arguments: ls-remote --tags --heads ssh://git@github.com/boringcrypto/BoringSolidity.git
  Directory: /home/runner/work/joe-core/joe-core
  Output:
  Warning: Permanently added the RSA host key for IP address '140.82.112.3' to the list of known hosts.
  git@github.com: Permission denied (publickey).
  fatal: Could not read from remote repository.
  
  Please make sure you have the correct access rights
  and the repository exists.
  Error: Process completed with exit code 128.
  </code></pre>
  <p>It seems like the machine doesnt have permission to install this dependency. This is how the dependency is defined in the package.json:</p>
  <pre><code>&quot;devDependencies&quot;: {
      &quot;@boringcrypto/boring-solidity&quot;: &quot;boringcrypto/BoringSolidity#e06e943&quot;,
  }
  </code></pre>
  <p>This is the .yaml file defining the action:</p>
  <pre><code>#  workflow pipeline
  name: sushiswap
  
  on: [&quot;push&quot;, &quot;pull_request&quot;]
  
  jobs:
    build:
      runs-on: ubuntu-latest
  
      strategy:
        fail-fast: false
        matrix:
          node: [&quot;14.x&quot;, &quot;12.x&quot;]
          os: [&quot;ubuntu-latest&quot;]
  
      steps:
        - uses: actions/checkout@v2
          with:
           ref: ${{github.event.pull_request.head.ref}}
           repository: ${{github.event.pull_request.head.repo.full_name}}
  
        - name: Nodejs  ${{ matrix.node-version }}
          uses: actions/setup-node@v2
          with:
            node-version: ${{ matrix.node-version }}
            check-latest: true
  
        - name: Install and Compile
          run: |
            yarn install
            yarn build
        - name: Test and Coverage
          run: |
            yarn test
    mythx:
      runs-on: ubuntu-latest
      env:
        MYTHX_API_KEY: ${{ secrets.MYTHX }}
  
      steps:
        - name: Nodejs 14.x
          uses: actions/setup-node@v2
          with:
            node-version: &quot;14.x&quot;
            check-latest: true
  
        - name: Set up Python 3.8
          uses: actions/setup-python@v2
          with:
            python-version: 3.8
  
        - name: Install MythX CLI
          run: python -m pip install mythx-cli
        - name: Print version info
          run: |
            python3 -V
            mythx version
        - uses: actions/checkout@v2
          with:
           ref: ${{github.event.pull_request.head.ref}}
           repository: ${{github.event.pull_request.head.repo.full_name}}
  
        - name: Install dependencies
          run: yarn install
  
        - name: Submit contracts
          run: mythx analyze
  </code></pre>