Add to changelog

Author: mulimoen

CHANGELOG.md

@@ -20,6 +20,7 @@
   with feature `have-parallel` instead of `have-direct`.
 - Fixed a missing symbol when building `hdf5-src` with `libz-sys`.
 - Fixed a bug where errors were only silenced on the main thread.
+- Fixed a memory leak when opening datasets.
 
 ## 0.8.1