fix(rubrics): Allow zero as min value for criteria weight

src/rubrics/infrastructure/requests/add_criteria_to_objective_request.go

@@ -2,5 +2,5 @@ package requests
 
 type AddCriteriaToObjectiveRequest struct {
 	Description string  `json:"description" validate:"required,min=8,max=510"`
-	Weight      float64 `json:"weight" validate:"required,numeric,min=0,max=100"`
+	Weight      float64 `json:"weight" default:"0" validate:"numeric,min=0,max=100"`
 }