update release notes

Author: aloctavodia

RELEASE-NOTES.md

@@ -15,6 +15,8 @@
 - `pm.DensityDist` no longer accepts the `logp` as its first position argument. It is now an optional keyword argument. If you pass a callable as the first positional argument, a `TypeError` will be raised (see [5026](https://github.com/pymc-devs/pymc3/pull/5026)).
 - `pm.DensityDist` now accepts distribution parameters as positional arguments. Passing them as a dictionary in the `observed` keyword argument is no longer supported and will raise an error (see [5026](https://github.com/pymc-devs/pymc3/pull/5026)).
 - The signature of the `logp` and `random` functions that can be passed into a `pm.DensityDist` has been changed (see [5026](https://github.com/pymc-devs/pymc3/pull/5026)).
+- Generalize BART. A BART variable can be combined with other random variables. The `inv_link` argument has been removed (see [4914](https://github.com/pymc-devs/pymc3/pull/4914)).
+- Move BART to its own module (see [5058](https://github.com/pymc-devs/pymc3/pull/5058)).
 - ...
 
 ### New Features
@@ -32,6 +34,8 @@
 - New experimental mass matrix tuning method jitter+adapt_diag_grad. [#5004](https://github.com/pymc-devs/pymc/pull/5004)
 - `pm.DensityDist` can now accept an optional `logcdf` keyword argument to pass in a function to compute the cummulative density function of the distribution (see [5026](https://github.com/pymc-devs/pymc3/pull/5026)).
 - `pm.DensityDist` can now accept an optional `get_moment` keyword argument to pass in a function to compute the moment of the distribution (see [5026](https://github.com/pymc-devs/pymc3/pull/5026)).
+-  BART: add linear response, increase number of trees fitted per step [5044](https://github.com/pymc-devs/pymc3/pull/5044).
+-  BART: add partial dependence plots and individual conditional expectation plots [5091](https://github.com/pymc-devs/pymc3/pull/5091).
 - ...
 
 ### Maintenance