inserted update in RELEASE-NOTES

Author: shkr

RELEASE-NOTES.md

@@ -7,7 +7,8 @@
 
 - Improve NUTS initialization `advi+adapt_diag_grad` and add `jitter+adapt_diag_grad` (#2643) 
 - Update loo, new improved algorithm (#2730)
-
+- New CSG (Constant Stochastic Gradient) approximate posterior sampling
+  algorithm added
 ### Fixes 
 - Fixed `compareplot` to use `loo` output. 
 - Add test for `model.logp_array` and `model.bijection` (#2724) 
@@ -249,6 +250,7 @@ Patricio Benavente <patbenavente@gmail.com>
 Raymond Roberts
 Rodrigo Benenson <rodrigo.benenson@gmail.com>
 Sergei Lebedev <superbobry@gmail.com>
+Shashank Shekhar <shashank.f1@gmail.com>
 Skipper Seabold <chris.fonnesbeck@vanderbilt.edu>
 Thomas Kluyver <takowl@gmail.com>
 Tobias Knuth <mail@tobiasknuth.de>