Adds feature to check if a branch name exists in a repository without…

[hostep]

… cloning it.

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I have a case where I want to verify before cloning a git repository that a branch name exists on the remote repo.
This adds such a feature.

It works with the command git ls-remote --heads {repo-url} {branch-name}
If the branch name is found in the output, we can assume the branch exists on the remote.

For example:

$ git ls-remote --heads https://github.com/gitonomy/foobar master
7e9ba14939b0ce67ab95d83e03bd64710db91ef4	refs/heads/master

$ git ls-remote --heads https://github.com/gitonomy/foobar invalid-branch-name

[lyrixx]

Thanks 👍🏼