pytest_plugin(fix[git_repo]): Add set_home dependency for child processes

why: Child processes spawned by git submodule operations need HOME set
to find $HOME/.gitconfig with protocol.file.allow=always configuration
what:
- Add set_home fixture dependency to git_repo fixture
- Fixes GitHub issue #509 for users of git_repo fixture

Author: tony

src/libvcs/pytest_plugin.py

@@ -701,6 +701,7 @@ def git_repo(
     projects_path: pathlib.Path,
     git_remote_repo: pathlib.Path,
     set_gitconfig: pathlib.Path,
+    set_home: None,  # Needed for child processes (e.g. submodules)
 ) -> GitSync:
     """Pre-made git clone of remote repo checked out to user's projects dir."""
     remote_repo_name = unique_repo_name(remote_repos_path=projects_path)