chore: update schema spec w/ new conditions

Author: heitorlessa

aws_lambda_powertools/utilities/feature_flags/schema.py

@@ -84,7 +84,9 @@ class SchemaValidator(BaseValidator):
     The value MUST contain the following members:
 
     * **action**: `str`. Operation to perform to match a key and value.
-    The value MUST be either EQUALS, STARTSWITH, ENDSWITH, IN, NOT_IN
+    The value MUST be either EQUALS, STARTSWITH, ENDSWITH, IN, NOT_IN,
+    KEY_IN_VALUE KEY_NOT_IN_VALUE VALUE_IN_KEY VALUE_NOT_IN_KEY
+
     * **key**: `str`. Key in given context to perform operation
     * **value**: `Any`. Value in given context that should match action operation.