Doc: versioning and deprecation policy (#277)

Add versioning and deprecation policy

Author: dweindl

doc/development.rst

@@ -0,0 +1,26 @@
+Development
+===========
+
+Versioning
+----------
+
+We use `Semantic Versioning <http://semver.org/>`_ with the modifications
+described under :ref:`deprecation_policy`.
+
+.. _deprecation_policy:
+
+Deprecation policy
+------------------
+
+petab aims to provide a stable API for users. However, not all features can be
+maintained indefinitely. We will deprecate features in minor releases and
+where possible, issue a warning when they are used. We will keep deprecated
+features for at least six months after the release that includes the
+respective deprecation warning and then remove them earliest in the next minor
+or major release. If a deprecated feature is the source of a major bug, we may
+remove it earlier.
+
+Python compatibility
+--------------------
+
+We follow `numpy's Python support policy <https://numpy.org/neps/nep-0029-deprecation_policy.html>`_.

doc/index.rst

@@ -14,6 +14,7 @@
    Changelog <CHANGELOG.md>
    how_to_cite
    license
+   development
 
 .. toctree::
    :maxdepth: 2