Add release notes to docs for past few releases

This commit adds release notes to the tempest-lib docs for the past 3
releases. This was overlooked for 0.4.0 and 0.3.0, so those were
included along with the recent 0.5.0 release.

Change-Id: I0b64b1467ebb44a13c9bf2cbbc1585a3221cc974

doc/source/index.rst

@@ -21,6 +21,31 @@ Contents:
 Release Notes
 =============
 
+0.5.0
+-----
+ * Support for specifying a prefix on the rand_name() function
+ * Migration of the ssh module from tempest
+ * A few cleanups and missing pieces for the auth.py module
+ * subunit-trace bug fix
+ * Improved unit tests and docstring coverage
+
+0.4.0
+-----
+ * A new console script entry point skip-tracker to identify @skip_because
+   decorators and query launchpad if the bug is closed or not
+ * Documentation Improvements
+ * A fix for rest client logging levels
+ * Adds the v2 and v3 token clients from tempest
+ * Adds the AuthProvider layer and credentials objects from tempest
+
+
+0.3.0
+-----
+ * Switch to using oslo.log instead of the oslo-incubator logging module
+ * Documentation improvements
+ * Handling of additional test result conditions in subunit-trace
+ * Addition of the data_utils module from tempest
+
 0.2.1
 -----
  * Fix subunit-trace to enable stdout passthrough