fix: bump OpenTelemetry Schema URL to 1.21.0

Fixes an error in the initialization of Authorino with tracing services enabled – "cannot merge resource due to conflicting Schema URL"

pkg/trace/exporter.go

@@ -13,7 +13,7 @@ import (
 	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
 	"go.opentelemetry.io/otel/sdk/resource"
 	"go.opentelemetry.io/otel/sdk/trace"
-	semconv "go.opentelemetry.io/otel/semconv/v1.17.0"
+	semconv "go.opentelemetry.io/otel/semconv/v1.21.0"
 )
 
 type Config struct {