Add inactive maintenance note. (#425)

Author: amageh

README.rst

@@ -26,6 +26,10 @@ respy
 
 ----
 
+*Note: respy is not under development anymore and only inactively maintained since 2021.
+Check out our* `GitHub organization <https://github.com/OpenSourceEconomics>`_ *to find  projects
+that are currently under development.*
+
 **respy** is an open source framework written in Python for the simulation and
 estimation of some finite-horizon discrete choice dynamic programming models. The group
 of models which can be currently represented in **respy** are called

docs/about_us.rst

@@ -10,6 +10,11 @@ an issue on Github, writing an `email`_ to or join our `zulipchat group
 .. _email: research-codes-respy.9b46528f81292a712fa4855ff362f40f.show-sender@streams.zulipchat.com
 
 
+.. note::
+    **respy** is not under development anymore and only inactively maintained since 2021.
+    Check out our `GitHub organization <https://github.com/OpenSourceEconomics>`_
+    to find projects that are currently under development.
+
 .. tabs::
 
    .. tab:: Team

docs/release_notes.rst

@@ -6,7 +6,14 @@ chronological order. We follow `semantic versioning <https://semver.org/>`_ and
 releases are available on `Anaconda.org
 <https://anaconda.org/opensourceeconomics/respy>`_.
 
-2.1.0 - 2020-
+
+.. note::
+    **respy** is not under development anymore and only inactively maintained since 2021.
+    Check out our `GitHub organization <https://github.com/OpenSourceEconomics>`_ to find
+    projects that are currently under development.
+
+
+2.1.0 - 2020
 -------------
 - :gh:`381` Implements exogenous processes (:ghuser:`MaxBlesch`, :ghuser:`mo2561057`).
 - :gh:`383` Fixes simulation with data and adds tests (:ghuser:`janosg`).