Update CHANGELOG.

CHANGELOG

 --------------------------------- CHANGELOG ----------------------------------
 
 HEAD
+  - Migrate to plugin_dbui 0.9.8.1
+  - This version is not backward compatible due to changes in plugin_dbui.
 
 0.9.6.3 (Nov 2016)
   - Add the script cold_start_096x.sql.
@@ -14,20 +16,20 @@ HEAD
   - Introduce iterator to scan list of authors and their affiliations.
   - Add the script fix_affiliation_keys_0960.py to migrate existing database.
   - Update the documentation, add an appendix for HAL Hidden,...
-  
+
 0.9.5.7 (Aug 2016)
   - Same as 0.9.5.6 but running with ExtJS 6.0.1
   - Require plugin_dbui 0.9.1 and plugin_extjs 6.0.1
   - Build via the script build-version6 in w2pext/utilities
-  
+
 0.9.5.6 (Jul 2016)
   - Update to harvest true inspirehep collection like HAL Hidden.
-  
+
 0.9.5.5 (Jun 2016)
   - Require plugin_dbui 0.9.0 or higher.
   - Change the javascript namespaces to Dbui and Limbra.
   - Add the author criteria in metrics and graphs selectors.
-  
+
 0.9.5.4 (Jun 2016)
   - Move to web2py 2.14.6, matplotlib 1.5.1 and pandas 0.18.1.
     The last version of web2py 2.14.6 requires plugin_dbui 0.8.3 or higher.