feat: add header to changelog template

CHANGELOG.md.jinja

@@ -1,3 +1,27 @@
+
+{#
+# /********************************************************************************
+# * Copyright (c) 2021,2023 Contributors to the Eclipse Foundation
+# *
+# * See the NOTICE file(s) distributed with this work for additional
+# * information regarding copyright ownership.
+# *
+# * This program and the accompanying materials are made available under the
+# * terms of the Apache License, Version 2.0 which is available at
+# * https://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.
+# *
+# * SPDX-License-Identifier: Apache-2.0
+# ********************************************************************************/
+#}
+
+
+
 {#- macro: render_commit -#}
 {%- macro render_commit(commit) -%}
 - {{ commit.convention.subject|default(commit.subject) }} (by {{ commit.author_name }}).