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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`


An example value could be "-o StrictHostKeyChecking=no"
              (although this particular option is better set by
              I(accept_hostkey)).
        type: str
        version_added: "1.5"
    key_file:
        description:
            - Specify an optional private key file path, on the target host, to use for the checkout.
        type: path
        version_added: "1.5"
    reference:
        description:
            - Reference repository (see "git clone --reference ...").
        version_added: "1.4"
    remote:
        description:
            - Name of the remote.
        type: str
        default: "origin"
    refspec:
        description:
            - Add an additional refspec to be fetched.
              If version is set to a I(SHA-1) not reachable from any branch
              or tag, this option may be necessary to specify the ref containing
              the I(SHA-1).
              Uses the same syntax as the C(git fetch) command.
              An example value could be "refs/meta/config".
        type: str
        version_added: "1.9"
    force: