* Fixes#21316, add testcase based on this
* Add option `--branch NAME` to git clone command in case of branch or
tag in combination with depth=1
* This option should work back to at least git 1.8 and thus on all
supported distributions
* Provide better warning if depth is dropped
* Cleanup git tests
* Split git tests in seperate files
* Remove use of repo_depth_url
* Use native yaml
* Remove unnecessary remote/local clones
* Fix newlines for yamllint
* If the hash is valid (full-length) but doesn't exist, git returns 128 instead of 1.
* Ensure git doesn't use hardlinks for shallow clones