Support for multiple glossary IDs #162

As of June 23, multiple glossaries should be supported by the v2/translate API. However, the Python library currently does not seem support that (using the latest version 1.30.0).

Simply using a list of IDs in the glossary paremeter expectedly raises an exception:
deepl.exceptions.DeepLException: Bad request, message: Value for 'glossary_id' not supported.

To work around that I've simply added a new check in the _check_language_and_formality method:

class Translator:
    def _check_language_and_formality[...]
        if isinstance(glossary, list):
            request_data["glossary_ids"] = glossary
        elif isinstance(glossary, GlossaryInfo) or isinstance(
                glossary, MultilingualGlossaryInfo
        ):
            request_data["glossary_id"] = glossary.glossary_id
        elif glossary is not None:
            request_data["glossary_id"] = glossary
    [...]

The API is happy to process the request afterwards :)