Adjust license header

Signed-off-by: David Schwilk <david.schwilk@bosch.io>

internal/models/signalenrichment/src/main/java/org/eclipse/ditto/internal/models/signalenrichment/DittoCachingSignalEnrichmentFacade.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019 Contributors to the Eclipse Foundation
+ * Copyright (c) 2021 Contributors to the Eclipse Foundation
  *
  * See the NOTICE file(s) distributed with this work for additional
  * information regarding copyright ownership.