Update RELEASE_NOTES.md

Author: corbett5

RELEASE_NOTES.md

@@ -4,10 +4,14 @@ Version vxx.yy.zz -- Release date 20yy-mm-dd
 * New features:
 
 * API Changes:
+  * You will now get a compilation error when performing certain undefined operations on rvalues, for example calling `toView` on an `Array` rvalue.
 
 * Build changes/improvements:
 
 * Bug fixes:
+  * Fixed indexing bug that produced a compilation error with GCC 10.
+  * Fixed a memory leak in CRSMatrix::assimilate.
+  * Fixed a memory leak in ArrayOfArraysView::free with non-trivially destructable values.
 
 Version v0.1.0 -- Release date 2020-10-13
 =========================================