Aliased git checkout as `gco`

plugins/git/git.plugin.zsh

@@ -8,6 +8,7 @@ alias gd='git diff | mate'
 alias gdv='git diff -w "$@" | vim -R -'
 alias gc='git commit -v'
 alias gca='git commit -v -a'
+alias gco='git checkout'
 alias gb='git branch'
 alias gba='git branch -a'
 alias gcount='git shortlog -sn'