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##### SUMMARY

The Git module encourages use of `StrictHostKeyChecking=no` with SSH, which makes the connection vulnerable to a MITM attack.

##### ISSUE TYPE

OpenSSH 7.5+ (2017-03-20) added a safer option which automatically accepts the key on first use but will not allow a MITM on subsequent connections: `StrictHostKeyChecking=accept-new` 

https://man.openbsd.org/ssh_config#StrictHostKeyChecking

It would be great if Ansible encouraged use of that mode by default in the documentation and to implement features such as the Git module's [`accept_hostkey`](https://github.com/ansible/ansible/blob/323d2adfcce9a53e906c2c4a40f6ac5fb32a0e68/lib/ansible/modules/git.py#L1103-L1108) feature.

##### ANSIBLE VERSION

```paste below
N/A
```

##### COMPONENT NAME
* `/modules/source_control/git.py`


if not force:
                module.fail_json(msg="Local modifications exist in the destination: " + dest + " (force=no).", **result)
            
            if not module.check_mode:
                reset(git_path, module, dest)
                result.update(changed=True, msg='Local modifications exist in the destination: ' + dest)
        
        if module.check_mode:
            remote_url = get_remote_url(git_path, module, dest, remote)
            remote_url_changed = remote_url and remote_url != repo and unfrackgitpath(remote_url) != unfrackgitpath(repo)
        else:
            remote_url_changed = set_remote_url(git_path, module, repo, dest, remote)
        result.update(remote_url_changed=remote_url_changed)
        if module.check_mode:
            remote_head = get_remote_head(git_path, module, dest, version, remote, bare)
            result.update(changed=(result['before'] != remote_head or remote_url_changed), after=remote_head)
            
            if module._diff:
                diff = get_diff(module, git_path, dest, repo, remote, depth, bare, result['before'], result['after'])
                if diff:
                    result['diff'] = diff
            module.exit_json(**result)
        else:
            fetch(git_path, module, repo, dest, version, remote, depth, bare, refspec, git_version_used, force=force)
        result['after'] = get_version(module, git_path, dest)
    
    
    if not bare:
        switch_version(git_path, module, dest, remote, version, verify_commit, depth, gpg_whitelist)