ElasticsearchDocumentStore with header returns got multiple values for keyword argument 'headers'

[yusyel]

Describe the bug
Getting header token from google.oauth2 & service account and passing ElasticsearchDocumentStore headers arg returns:

TypeError: elasticsearch.Elasticsearch() got multiple values for keyword argument 'headers'

Code:

def get_token():
    credentials = service_account.IDTokenCredentials.from_service_account_file(
        SERVICE_ACCOUNT_FILE, target_audience=SEARCH)
    request = google.auth.transport.requests.Request()
    credentials.refresh(request)
    token = credentials.token
    header = {
    'Authorization': f'Bearer {token}'
    }
    return header

ElasticsearchDocumentStore(hosts = SEARCH, embedding_similarity_function="cosine", index=index_name, headers=header)

I tested with Elasticsearch client same header works.

However, just passing token to bearer_auth works. Which I used in my project.

Describe your environment (please complete the following information):

• OS: debian
• Haystack version: haystack 2.6.0
• Integration version: elasticsearch-haystack 1.0.0