title: Cocoapods subspec issue: None of your spec sources contain a spec satisfying the dependency
body: <p>I modified a repo on Github to integrate a swift version of my library.</p>
  
  <p><a href="https://github.com/iDevelopper/PBRevealViewController" rel="noreferrer">https://github.com/iDevelopper/PBRevealViewController</a></p>
  
  <p>However when in a new project I try to pod install I get the error:</p>
  
  <p>[!] Unable to satisfy the following requirements:</p>
  
  <ul>
  <li><code>PBRevealViewController/Swift (= 1.2.3)</code> required by <code>Podfile</code></li>
  </ul>
  
  <p>None of your spec sources contain a spec satisfying the dependency: <code>PBRevealViewController/Swift (= 1.2.3)</code>.</p>
  
  <p>You have either:
   * out-of-date source repos which you can update with <code>pod repo update</code> or with <code>pod install --repo-update</code>.
   * mistyped the name or version.
   * not added the source repo that hosts the Podspec to your Podfile.</p>
  
  <p>Note: as of CocoaPods 1.0, <code>pod repo update</code> does not happen on <code>pod install</code> by default.</p>
  
  <p>Some helps are welcome!</p>
  
  <p>Please see the Cocoapods issue:</p>
  
  <p><a href="https://github.com/CocoaPods/CocoaPods/issues/6970#event-1213956994" rel="noreferrer">https://github.com/CocoaPods/CocoaPods/issues/6970#event-1213956994</a></p>