title: Authentication issue with repo accessed from Spring Cloud Config Server hosted on GitHub
body: <p>I'm hosting a configuration in a repo on GitHub. If I keep the repo public all's good, but if I make it private I face:</p>
  
  <pre><code>org.eclipse.jgit.errors.TransportException: 
   https://github.com/my-user/my-repo:
   Authentication is required but no CredentialsProvider has been registered
  </code></pre>
  
  <p>the property I use to target the repo is </p>
  
  <pre><code>spring.cloud.config.server.git.uri=https://github.com/my-user/my-repo
  </code></pre>
  
  <p>What should I do to configure this properly with the private repo, thanks</p>