[omemo] Update CHANGELOG & manifest.ini

omemo/CHANGELOG

+2.6.68 / 2019-11-18
+- Correctly handle presence in anonymous rooms
+- Fix error in config dialog if no account is available
+
 2.6.67 / 2019-11-10
 - Correctly handle MAM Messages in anonymous rooms
 - Show error when message was not encrypted for our device

omemo/manifest.ini

 [info]
 name: OMEMO
 short_name: omemo
-version: 2.6.67
+version: 2.6.68
 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 dependencies, you can find install instructions for your system in the Github Wiki.
 authors: Bahtiar `kalkin-` Gadimov <bahtiar@gadimov.de>
  Daniel Gultsch <daniel@gultsch.de>