docs: Moving release note to docs/source, so it is visible on ndnSIM website

Change-Id: I211ac6e3a723a9b5f7310741334818af7fac2b19
diff --git a/docs/source/tutorial.rst b/docs/source/tutorial.rst
index ac809c1..9b777eb 100644
--- a/docs/source/tutorial.rst
+++ b/docs/source/tutorial.rst
@@ -38,6 +38,7 @@
     :glob:
 
     meta/*
+    RELEASE_NOTES
 
 
 -------