title: Swift package manager - Has no manifest error
body: <p>I created a Swift Package Manager library, and deployed it on my GitLab with a tag number 0.1.0. I'm now trying to add this package to my new vapor project by adding:</p>
  
  <pre><code>.package(url: "http://mygit.git/", from: "0.1.0").
  </code></pre>
  
  <p>When I try to make a "vapor update" I get a backgroundExecute error saying that my SPM has no manifest for version 0.1.0…</p>
  
  <p>Any ideas? Thanks in advance!</p>