title: GitLab pull submodules inside CI
body: <p>I have a GitLab project that utilises GitLab CI.
  The project also uses submodules, both the project and it's submodules are under the same GitLab account.</p>
  
  <p>Here is my <code>.gitmodules</code> file</p>
  
  <pre><code>[submodule "proto_contracts"]
      path = proto_contracts
      url = https://gitlab.com/areller/proto_contracts.git
  </code></pre>
  
  <p>I also have this piece in the .gitlab-ci.yml file</p>
  
  <pre><code>variables:
    GIT_SUBMODULE_STRATEGY: recursive
  </code></pre>
  
  <p>However, when i run the CI I get this error</p>
  
  <pre><code>fatal: could not read Username for 'https://gitlab.com': No such device or address
  </code></pre>
  
  <p>Both the project and the submodules are in a private repository so you would expect to be prompted for authentication, but as I've mentioned, the project and the submodule are under the same account and one of the runner's jobs is to clone the original repository</p>
  
  <p><a href="https://i.stack.imgur.com/9zc2s.png" rel="noreferrer"><img src="https://i.stack.imgur.com/9zc2s.png" alt="enter image description here"></a></p>
  
  <p>So it's odd that it's unable to reach the submodule
  Is there a way around it?</p>