Mention roadmap [ci skip]

pllim · web-flow · commit 03d7c2ed8434 · 2020-07-31T12:52:00.000-04:00
diff --git a/doc/source/index.rst b/doc/source/index.rst
@@ -4,6 +4,12 @@
 Astrolib PySynphot (**pysynphot**)
 **********************************
 
+.. note::
+
+    This package is no longer actively developed. See
+    `package roadmap <https://github.com/spacetelescope/pysynphot/blob/master/ROADMAP.md>`_
+    for more information.
+
 Introduction
 ============
 
