Abillity to clone git repository in non-empty folder [feature-request]

When I try to clone a repository using the pygit2.clone_repository function, it keeps giving me a '.' exists and is not an empty directory error. I can solve this by appending a backward slash / to the pathstr. I, however, for my project, need to be able to clone multiple repositories next to each other inside a catkin workspace. There are several easy workarounds for this problem, but I wondered if this is supported out of the box. I think supporting this out of the box would be more in line with how the bash git client clones git repositories.

How to reproduce

1. Run the following code in python.

import pygit2
repo_url = "https://bitbucket.org/theconstructcore/spawn_robot_tools.git"
pygit2.clone_repository(repo_url, ".", bare=True)

2. See the not empty folder error.

Example work-around

import pygit2
repo_url = "https://bitbucket.org/theconstructcore/spawn_robot_tools.git"
pygit2.clone_repository(repo_url, "./"+repo_url.split("/")[-1].replace(".git", ""), bare=True)

首先运行使用 "." 和 bare=True 的 pygit2.clone_repository Python 复现。检查第 165 行附近 pygit2/init.py 中 clone_repository 的定义；当克隆到所示的非空文件夹时无需 workaround 即可正常工作，同时保留现有行为，即表示更改完成。