Bring the project back to REUSE compliance

Signed-off-by: Wayne Beaton <[email protected]>

.reuse/dep5

@@ -63,6 +63,10 @@ Files: core/src/test/java/test_data_package-lock-v2.json
 Copyright: 2019 Contributors to the Eclipse Ditto Project
 License: EPL-2.0
 
+Files: core/src/test/java/test_data_package-lock-v3.json
+Copyright: 2019 Contributors to the Eclipse Langium Project
+License: MIT
+
 Files: core/src/test/java/test_data_asn1crypto.json
 Copyright: 2021 Contributors to pypi.org
 License: MIT
@@ -99,3 +103,7 @@ Files: maven-plugin/src/it/**/pom.xml
 Copyright: 2022 Red Hat
 License: EPL-2.0
 
+Files: CHANGELOG.md
+Copyright: 2023 The Eclipse Foundation
+License: EPL-2.0
+