Fix compilation: define RPC_RESPONSE_STATUS_CODE inline instead of importing from semconv-incubating

Author: trask

instrumentation/grpc-1.6/library/src/main/java/io/opentelemetry/instrumentation/grpc/v1_6/GrpcAttributesExtractor.java

@@ -9,7 +9,6 @@
 import static io.opentelemetry.instrumentation.api.internal.SemconvStability.emitStableRpcSemconv;
 import static io.opentelemetry.instrumentation.grpc.v1_6.CapturedGrpcMetadataUtil.lowercase;
 import static io.opentelemetry.instrumentation.grpc.v1_6.CapturedGrpcMetadataUtil.requestAttributeKey;
-import static io.opentelemetry.semconv.incubating.RpcIncubatingAttributes.RPC_RESPONSE_STATUS_CODE;
 
 import io.grpc.Status;
 import io.opentelemetry.api.common.AttributeKey;
@@ -24,6 +23,8 @@ final class GrpcAttributesExtractor implements AttributesExtractor<GrpcRequest,
   // copied from RpcIncubatingAttributes
   private static final AttributeKey<Long> RPC_GRPC_STATUS_CODE =
       AttributeKey.longKey("rpc.grpc.status_code");
+  private static final AttributeKey<String> RPC_RESPONSE_STATUS_CODE =
+      AttributeKey.stringKey("rpc.response.status_code");
 
   private final GrpcRpcAttributesGetter getter;
   private final List<String> capturedRequestMetadata;