Update 0.6 release notes

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

@@ -23,6 +23,7 @@ _Under development._
 
 * [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.
 * An alias for the [`#reverse`](pathname:///api/dev/Marten/Handlers/Base.html#reverse(*args%2C**options)-instance-method) handler method ([`#url`](pathname:///api/dev/Marten/Handlers/Base.html#url(name%3AString|Symbol%2C**kwargs)%3AString-instance-method)) was introduced.
+* A [Referrer-Policy middleware](../../handlers-and-http/reference/middlewares.md#referrer-policy-middleware) was introduced to make it possible to automatically set the Referrer-Policy header in responses generated by handlers.
 
 #### Templates