Add API release 2023-04

Author: mkevinosullivan

shopify/api_version.py

@@ -33,6 +33,7 @@ def define_known_versions(cls):
         cls.define_version(Release("2022-07"))
         cls.define_version(Release("2022-10"))
         cls.define_version(Release("2023-01"))
+        cls.define_version(Release("2023-04"))
 
     @classmethod
     def clear_defined_versions(cls):