Update Changelog for hotfix version

Changelog

-CHANGELOG for version 0.12.rc6
+CHANGELOG for hotfix version 0.12.1
 
-Add self.poolsize for kamaki.clients.Client
-
-CHANGELOG for version 0.12.rc5
-
-Add ip attach/detach (shortcuts for port create/delete)
-
-CHANGELOG for version 0.12.rc4
-
-Fix syntax errors in network commands
-
-CHANGELOG for version 0.12.rc3
-
-Check clients unittests
-
-CHANGELOG for version 0.12rc3
-
-Correct keys in HTTP bodies on network-related requests
+- Various minor typos
+- Rename comand group "kamaki project membership" --> "kamaki membership"
+- Add docs for astakos-related commands:
+    user, quota, resources, project, membership
 
 CHANGELOG for version 0.12
 
 Bug Fixes:
--In file list, the path or prefix was converted to boolean value. Fixed.
--Thread options did not work [#4616]
+- In file list, the path or prefix was converted to boolean value. Fixed.
+- Thread options did not work [#4616]
+- Various minor typos
 
 Changes:
 1. Make astakosclient a mantatory requirement for kamaki [#4312]
@@ -35,6 +23,8 @@ Changes:
 6. Deprecate (with note) server stats/console/addr (move to server info)
 7. A vanilla kamaki call now shows only the available commands instead of
     loading a shell [#4612]
+8. Add self.poolsize at kamaki.clients.Client
+9. Add ip attach/detach (shortcuts for port create/delete)
 
 Features: