work-around: generate dummy javadoc JAR file to publish on Maven Central

slizaa-server/slizaa-server-spec/javadoc/readme.txt

@@ -1 +1,19 @@
-We must generate a -javadoc JAR file to publish on Maven Central
+====
+    slizaa-server-spec - Slizaa Static Software Analysis Tools
+    Copyright © 2019 Code-Kontor GmbH and others ([email protected])
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program 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 Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+====
+
+====