refactor(checkoutservice): use exception.message key from semantic co…

…nvention (open-telemetry#1430)

src/checkoutservice/main.go

@@ -7,7 +7,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	semconv "go.opentelemetry.io/otel/semconv/v1.24.0"
 	"net"
 	"net/http"
 	"os"
@@ -16,6 +15,7 @@ import (
 	"time"
 
 	"go.opentelemetry.io/otel/attribute"
+	semconv "go.opentelemetry.io/otel/semconv/v1.24.0"
 	"go.opentelemetry.io/otel/trace"
 
 	"github.com/IBM/sarama"
@@ -243,7 +243,7 @@ func (cs *checkoutService) PlaceOrder(ctx context.Context, req *pb.PlaceOrderReq
 	var err error
 	defer func() {
 		if err != nil {
-			span.AddEvent("error", trace.WithAttributes(attribute.String("exception.message", err.Error())))
+			span.AddEvent("error", trace.WithAttributes(semconv.ExceptionMessageKey.String(err.Error())))
 		}
 	}()