language() request needs to be 'GET' in APIS.py

[Isaha-Miller]

urllib is throwing a urllib.error.HTTPError: HTTP Error 405: METHOD NOT ALLOWED error because languages() is not specifying a GET request. The fix is to change line 82 req = request.Request(url, data=url_params.encode()) to an explicit GET.

def languages(self):
        """Retrieve list of supported languages.

        Returns: A list of available languages ex. [{"code":"en", "name":"English"}]
        """

        url = self.url + "languages"

        params = dict()

        if self.api_key is not None:
            params["api_key"] = self.api_key

        url_params = parse.urlencode(params)

        req = request.Request(url, data=url_params.encode(),method="GET")

        response = request.urlopen(req)

        response_str = response.read().decode()

        return json.loads(response_str)```

[PJ-Finlay]

I think the LibreTranslate API changed slightly. We had this issue with the Python API too. It's fixed in the Python API so maybe we can just copy code from there. If someone makes a pull request for this I'll merge it.