GHSA-PG4W-G64P-QWHJ gix and gitoxide's symlinked .gitmodules are followed and parsed from outside of the repository

Summary attachments: pocs.zip When Repository::submodules loads submodule metadata, it prefers the worktree .gitmodules file if that path exists. In the current implementation, the path is read with std::fs::read, which follows symlinks. As a result, a repository can present a symlinked .gitmodul...