feat(git-aliases): add checkout with username

this can be useful for creating a branch with a common prefix

aliases/available/git.aliases.bash

@@ -65,6 +65,7 @@ alias gco='git checkout'
 alias gcom='git checkout master'
 alias gcb='git checkout -b'
 alias gcob='git checkout -b'
+alias gcobu="git checkout -b ${USER}/"
 alias gct='git checkout --track'
 alias gcpd='git checkout master; git pull; git branch -D'
 alias gexport='git archive --format zip --output'