title: Azure DevOps Build Submodule
body: <p>I have a private bitbucket repo that is connected to the Azure DevOps Build Pipeline. 
  The private repo has a submodule connected to a public Github repo.</p>
  
  <p>Both repositories are accessed via SSH.</p>
  
  <p>I have ticked the clone submodules box in DevOps.</p>
  
  <p>How do I provide an SSH key to Azure DevOps so it will clone the submodule?</p>