Updated release notes

Author: svermeulen

Documentation/ReleaseNotes.md

@@ -1,6 +1,21 @@
 
 # <a id="release-notes"></a>Release Notes
 
+## Version 9.1.0 (October 13, 2019)
+
+New Features
+* Changed SceneLoader methods to use optional arguments instead of overloads to allow only specifying parameters of interest
+* Added CustomPoolableManager class to allow passing arguments to IPoolable<T> derived classes
+* Added non generic variant of DeclareSignal method
+* Added support for NSubstitute usage with auto mocking
+
+Bug fixes
+* Fixed exception that would sometimes occur in multi-threaded applications
+* Fixed some issues related to game object subcontainers and circular dependencies
+* Changed the PreInstall/PostInstall/PreResolve/PostResolve methods in ProjectContext to be static so they can be used before initialization occurs
+* Fixed IL2CPP issue related to default values
+* Other minor bug fixes
+
 ## Version 9.0.0 (April 21, 2019)
 
 This is the beginning of zenject support for Unity 2019.  For Unity 2018.4.x use 8.0.x versions of zenject.  For Unity 2017.4.x use 6.6.X versions of zenject.