Push an empty branch should work

When we push an empty branch, server don’t accept it.

Reproduce

git checkout -b myBranch && git push origin myBranch

Investigation

Multiple problems here:

• go-git seams to not create the branch in the temporary storer
• gitroot try to run plugin on the previous commit (has it don’t find an old commit)

Linked to

force push main need commit

After

Think to reactive tests in test-suite find the two # TODO