Load plugin from master.

    $ antigen-bundle $PLUGIN_DIR

    Cloning into '.+?'\.\.\. (re)
    done.
    $ hehe
    hehe

  Load the plugin again. Just to see nothing happens.
  
    $ antigen-bundle $PLUGIN_DIR
    $ hehe
    hehe

  Update the plugin.

    $ cat > $PLUGIN_DIR/aliases.zsh <<EOF

    > alias hehe='echo hehe, updated'
    > EOF
    $ pg commit -am 'Updated message'
    \[master [a-f0-9]{7}\] Updated message (re)
     1 file changed, 1 insertion(+), 1 deletion(-)
  
  Update bundles.
  
    $ antigen-update

    **** Pulling */test-plugin (glob)
    From */test-plugin (glob)
       ???????..???????  master     -> origin/master (glob)
    Updating ???????..??????? (glob)

    Fast-forward
     aliases.zsh |    2 +-
     1 file changed, 1 insertion(+), 1 deletion(-)

  
  Confirm there is still only one repository.
  
    $ ls $ADOTDIR/repos | wc -l
    1
  
  The new alias should not activate.
  
    $ hehe
    hehe