Add missing _api suffix in apis.j2 import path

Author: pdv

.generator/src/generator/templates/apis.j2

@@ -1,6 +1,6 @@
 {%- for api in apis %}
 {%- set classname = api|class_name %}
-from {{ package }}.{{ version }}.api.{{ api|safe_snake_case }} import {{ classname }}
+from {{ package }}.{{ version }}.api.{{ api|safe_snake_case }}_api import {{ classname }}
 {%- endfor %}