Update release notes for 0.3.6, fix koji invocation

.gitlab-ci.yml

@@ -141,7 +141,7 @@ cc7-koji:
   stage: koji
   image: gitlab-registry.cern.ch/linuxsupport/cc7-base
   script:
-    - yum install -y koji --disablerepo=extras
+    - yum install -y koji
     - yum install -y git rpm-build python
     - mkdir ~/.koji
     - cp ci/koji/config ~/.koji

CHANGELOG.md

 # Changelog
 All notable changes to this project will be documented in this file.
 
-## Unreleased
-- Better memory management and recycling, putting less pressure on the global
+## 0.3.6 (2019-03-21)
+- Improved memory management and recycling, putting less pressure on the global
 memory allocator.
 - Addition of pub/sub support, commands implemented: ``PUBLISH``, ``SUBSCRIBE``,
   ``PSUBSCRIBE``, ``UNSUBSCRIBE``, ``PUNSUBSCRIBE``
 - Addition of ``--steal-state-machine`` flag to ``quarkdb-create`` to make
-  transition from bulkload mode to raft easier.
+  transition out of bulkload mode easier and less error-prone.
 - Updated rocksdb to v5.18.3.
 
 ## 0.3.5 (2018-11-28)