Add missing license header

Author: adangel

src/main/resources/net/sourceforge/pmd/util/fxdesigner/designer.properties

@@ -1,3 +1,7 @@
+#
+# BSD-style license; for more info see http://pmd.sourceforge.net/license.html
+#
+
 # Loaded in net.sourceforge.pmd.util.fxdesigner.DesignerVersion
 # The variables are replaced by resource filtering, see https://maven.apache.org/plugins/maven-resources-plugin/examples/filter.html