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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`


cmd = [git_path, 'submodule', 'foreach', git_path, 'rev-parse', version]
    (rc, out, err) = module.run_command(cmd, cwd=dest)
    if rc != 0:
        module.fail_json(
            msg='Unable to determine hashes of submodules',
            stdout=out,
            stderr=err,
            rc=rc)
    submodules = {}
    subm_name = None
    for line in out.splitlines():
        if line.startswith("Entering '"):
            subm_name = line[10:-1]
        elif len(line.strip()) == 40:
            if subm_name is None:
                module.fail_json()
            submodules[subm_name] = line.strip()
            subm_name = None
        else:
            module.fail_json(msg='Unable to parse submodule hash line: %s' % line.strip())
    if subm_name is not None:
        module.fail_json(msg='Unable to find hash for submodule: %s' % subm_name)
    return submodules
def clone(git_path, module, repo, dest, remote, depth, version, bare,