🐛 Makes ResourceTypes serialisable

For API calls with ResourceTypes as arguments, this Enum must be converted to string.

PR not tested as I'm on my phone 

Fix #407

aiohue/v2/models/resource.py

@@ -4,7 +4,7 @@
 from enum import Enum
 
 
-class ResourceTypes(Enum):
+class ResourceTypes(str, Enum):
     """
     Type of the supported resources.