update release notes

Author: OriolAbril

RELEASE-NOTES.md

@@ -23,6 +23,8 @@
 - Dropped the outdated 'nuts' initialization method for `pm.sample` (see [#3863](https://github.com/pymc-devs/pymc3/pull/3863)).
 - Moved argument division out of `NegativeBinomial` `random` method. Fixes [#3864](https://github.com/pymc-devs/pymc3/issues/3864) in the style of [#3509](https://github.com/pymc-devs/pymc3/pull/3509).
 - The Dirichlet distribution now raises a ValueError when it's initialized with <= 0 values (see [#3853](https://github.com/pymc-devs/pymc3/pull/3853)).
+- End of sampling report now uses `arviz.InferenceData` internally and avoids storing
+  pointwise log likelihood (see [#3883](https://github.com/pymc-devs/pymc3/pull/3883))
 
 ## PyMC3 3.8 (November 29 2019)