title: "Updates were rejected because the tag already exists" when attempting to push in SourceTree
body: <p>When attempting to Push via Source Tree, I get the following error:</p>
  
  <pre><code>git -c diff.mnemonicprefix=false -c core.quotepath=false -c credential.helper=sourcetree push -v --tags origin refs/heads/master:refs/heads/master 
  Pushing to https://user@github.com/repo.git
  To https://user@github.com/repo.git
   = [up to date]      master -&gt; master
  ...
   ! [rejected]        example_tag -&gt; example_tag (already exists)
  updating local tracking ref 'refs/remotes/origin/master'
  error: failed to push some refs to 'https://user@github.com/repo.git'
  hint: Updates were rejected because the tag already exists in the remote.
  Completed with errors, see above
  </code></pre>
  
  <p>I didn't make any changes to this tag as far as I know. How can I fix this?</p>