Add GPL3 header to helloworld.go

test/integration/library/helloworld.go

@@ -1,3 +1,18 @@
+// This file is part of Ansible
+//
+// Ansible is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Ansible is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
+
 package main
 
 import (