Fix boilerplate license years for generated files

Signed-off-by: Angel Misevski <[email protected]>

Author: amisevsk

hack/boilerplate.go.txt

@@ -1,5 +1,5 @@
 //
-// Copyright (c) 2019-2020 Red Hat, Inc.
+// Copyright (c) 2019-2021 Red Hat, Inc.
 // This program and the accompanying materials are made
 // available under the terms of the Eclipse Public License 2.0
 // which is available at https://www.eclipse.org/legal/epl-2.0/