[omemo] Update CHANGELOG & manifest.ini

omemo/CHANGELOG

+2.3.0 / 2017-05-07
+- Make plugin compatible with Gajims encryption API
+
 2.2.1 / 2017-04-15
 - Recognize aesgcm uri scheme
 

omemo/manifest.ini

 [info]
 name: OMEMO
 short_name: omemo
-version: 2.2.1
+version: 2.3.0
 description: OMEMO is an XMPP Extension Protocol (XEP) for secure multi-client end-to-end encryption based on Axolotl and PEP. You need to install some dependencys, you can find install instructions for your system in the Github Wiki.
 authors: Bahtiar `kalkin-` Gadimov <bahtiar@gadimov.de>
  Daniel Gultsch <daniel@gultsch.de>