Move/rename an existing local branch reference.
The new branch name will be checked for validity.
See git_tag_create()
for rules about valid names.
Note that if the move succeeds, the old reference object will not
be valid anymore, and should be freed immediately by the user using
git_reference_free()
.
Target name of the branch once the move is performed; this name is validated for consistency.
Overwrite existing branch.
0 on success, GIT_EINVALIDSPEC or an error code.