Update license_header_template.

Add SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause

Signed-off-by: Achim Kraus <achim.kraus@cloudcoap.net>

license_header_template.txt

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) <year (e.g. 2020)> <(company) name> and others.
+ * Copyright (c) <year (e.g. 2022)> Contributors to the Eclipse Foundation.
  * 
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v2.0
@@ -10,8 +10,8 @@
  * and the Eclipse Distribution License is available at
  *    http://www.eclipse.org/org/documents/edl-v10.html.
  * 
- * Contributors:
- *    <(company) name> - initial creation
+ * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
+ *
  ******************************************************************************/
 
-Please replace all <symbolic name> tags with the information proper for you!
+Please replace <year> tag with the current year!