Updated change log for 0.1.2 release. (#15)

Signed-off-by: Jakob Naucke <jakob.naucke@ibm.com>

docs/changes.rst

@@ -22,17 +22,24 @@
 Change log
 ----------
 
-Version 0.1.1
+Version 0.1.2
 ^^^^^^^^^^^^^
 
 Released: 2018-08-23
 
-Initial PyPI release (0.1.0 was for testing purposes)
+**Enhancements:** The description now instructs the user to ``pip3 install zhmc-prometheus-exporter`` instead of running a local install from the cloned repository. It also links to the stable version of the documentation rather than to the latest build.
 
 **Known issues:** See the `list of open issues`_.
 
 .. _list of open issues: https://github.com/zhmcclient/zhmc-prometheus-exporter/issues
 
+Version 0.1.1
+^^^^^^^^^^^^^
+
+Released: 2018-08-23
+
+Initial PyPI release (0.1.0 was for testing purposes)
+
 Version 0.1.0
 ^^^^^^^^^^^^^