Update 0.6 release notes

docs/docs/the-marten-project/release-notes/0.6.md

@@ -19,6 +19,10 @@ _Under development._
 
 ### Minor features
 
+#### Models and databases
+
+* [Query sets](../../models-and-databases/queries.md) now support XOR operations when [performing complex queries involving `q` expressions](../../models-and-databases/queries.md#complex-filters-with-q-expressions). Additionally, combining query sets using the XOR operator (`^`) is now also supported (see [`#^ (XOR)`](../../models-and-databases/reference/query-set.md#-xor)).
+
 #### Handlers and HTTP
 
 * [Session stores](../../handlers-and-http/sessions.md) now make it possible to easily configure when session entries expire through the use of the [`#expires_at=`](pathname:///api/dev/Marten/HTTP/Session/Store/Base.html#expires_at%3D(value%3ATime)-instance-method), [`#expires_at_browser_close=`](pathname:///api/dev/Marten/HTTP/Session/Store/Base.html#expires_at_browser_close%3D(value%3ABool)-instance-method), and [`#expires_in=`](pathname:///api/dev/Marten/HTTP/Session/Store/Base.html#expires_in%3D(value%3ATime%3A%3ASpan)-instance-method) methods. Please refer to [Customizing session expiry times](../../handlers-and-http/sessions.md#customizing-session-expiry-times) to learn more about this capability.