Update schema/workflow.yaml

Co-authored-by: Matthias Pichler <m.pichler@warrify.com>
Signed-off-by: Francisco Javier Tirado Sarti <ftirados@redhat.com>

Author: fjtirado

schema/workflow.yaml

@@ -1297,7 +1297,7 @@ $defs:
         description: The event's payload data
         oneOf:
           - $ref: '#/$defs/runtimeExpression'
-          - type: object 
+          - {}
     additionalProperties: true
   eventConsumptionStrategy:
     type: object