Start updating release docs

docs/upgrading.rst

@@ -3,10 +3,10 @@
 Upgrade guide
 =============
 
-Upgrading to 0.8.0 (not released yet)
--------------------------------------
+Upgrading to 0.8beta1
+---------------------
 
-When upgrading to version 0.8.0 OpenAppStack will be renamed to its final name:
+When upgrading to version 0.8beta1 OpenAppStack will be renamed to its final name:
 *Stackspin*. This comes with many changes, some of which need to be applied
 manually.