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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 version in get_annotated_tags(git_path, module, dest):
        git_sub = "verify-tag"
    else:
        git_sub = "verify-commit"
    cmd = "%s %s %s" % (git_path, git_sub, version)
    if gpg_whitelist:
        cmd += " --raw"
    (rc, out, err) = module.run_command(cmd, cwd=dest)
    if rc != 0:
        module.fail_json(msg='Failed to verify GPG signature of commit/tag "%s"' % version, stdout=out, stderr=err, rc=rc)
    if gpg_whitelist:
        fingerprint = get_gpg_fingerprint(err)
        if fingerprint not in gpg_whitelist:
            module.fail_json(msg='The gpg_whitelist does not include the public key "%s" for this commit' % fingerprint, stdout=out, stderr=err, rc=rc)
    return (rc, out, err)
def get_gpg_fingerprint(output):
    """Return a fingerprint of the primary key.
    Ref:
    https://git.gnupg.org/cgi-bin/gitweb.cgi?p=gnupg.git;a=blob;f=doc/DETAILS;hb=HEAD#l482
    """
    for line in output.splitlines():
        data = line.split()
        if data[1] != 'VALIDSIG':
            continue
        
        data_id = 11 if len(data) == 11 else 2
        return data[data_id]
def git_version(git_path, module):