Expose themes submodule

Author: tcbegley

dash_bootstrap_components/__init__.py

@@ -2,6 +2,7 @@
 import os
 import sys
 
+from dash_bootstrap_components import themes  # noqa
 from dash_bootstrap_components import _components
 from dash_bootstrap_components._components import *  # noqa
 from dash_bootstrap_components._table import _generate_table_from_df