fix: add default value for access token in HttpClient init (ClickHous…

…e#448)

Signed-off-by: Lukas Thaler <113890185+lukasthalerINNIO@users.noreply.github.com>

clickhouse_connect/driver/httpclient.py

@@ -54,7 +54,7 @@ def __init__(self,
                  username: str,
                  password: str,
                  database: str,
-                 access_token: Optional[str],
+                 access_token: Optional[str] = None,
                  compress: Union[bool, str] = True,
                  query_limit: int = 0,
                  query_retries: int = 2,