chore: Bump version, update release notes

Author: riddell-stan

doc/whats_new.rst

@@ -6,7 +6,7 @@
  What's New
 ============
 
-v2.19.1.0 (25. Oct 2019)
+v2.19.1.1 (25. Oct 2019)
 ========================
 - Update Stan source to v2.19.1 (`release notes <https://github.com/stan-dev/stan/releases/tag/v2.19.1>`_)
 - Fix order of per-chain values returned by Fit ``summary`` (`GH646 <https://github.com/stan-dev/pystan/issues/646>`_)

pystan/__init__.py

@@ -19,4 +19,4 @@
 
 # following PEP 386
 # See also https://docs.openstack.org/pbr/latest/user/semver.html
-__version__ = '2.19.1.0'
+__version__ = '2.19.1.1'