doc: update release note 0.6.2

Author: hredestig

release-notes/0.6.2.md

@@ -2,6 +2,10 @@
 
 ## Fixes
 
+- Fix in the ordering and rounding of FVA summary
+  [#525](https://github.com/opencobra/cobrapy/pull/525)
+- Shared memory, improve speed during sampling
+  [#521](https://github.com/opencobra/cobrapy/pull/521)
 - Debug `model.remove_reactions` to properly work with context manager.
   This lead to the deprecation of `reaction.delete` as this was not compatible
   with the concept of being able to later revert the change.