Checkstyle: @author tags are deprecated

Author: garydgregory

src/conf/checkstyle.xml

@@ -139,4 +139,12 @@
 
   </module>
 
+  <!-- @author tags are deprecated -->
+  <module name="RegexpSingleline">
+    <property name="format" value="^\s+\*\s+@author\s" />
+    <property name="message" value="Deprecated @author tag" />
+    <property name="fileExtensions" value="java" />
+    <property name="severity" value="warning" />
+  </module>
+
 </module>