[SDFAB-187] Add UpfProgrammable interface in ONOS core

Change-Id: Icef23a14015bb0ebe33ebe57eadecaaadc8eebd3
diff --git a/core/api/src/main/java/org/onosproject/net/behaviour/upf/package-info.java b/core/api/src/main/java/org/onosproject/net/behaviour/upf/package-info.java
new file mode 100644
index 0000000..805e149
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/behaviour/upf/package-info.java
@@ -0,0 +1,20 @@
+/*
+ * Copyright 2021-present Open Networking Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * 3GPP User Plane Function behaviors and related classes.
+ */
+package org.onosproject.net.behaviour.upf;