Forward-port 2.0.3 release notes.

docs/source/releases/index.rst

     v2.0
     v2.0.1
     v2.0.2
+    v2.0.3
 
 
 1.6 release branch

docs/source/releases/v2.0.3.rst

+=======================
+Oscar 2.0.3 release notes
+=======================
+
+:release: 2019-10-08
+
+This is Oscar 2.0.3, a bugfix release.
+
+Bug fixes
+=========
+
+- Added an ``OSCAR_THUMBNAIL_DEBUG`` setting to control whether the
+  ``oscar_thumbnail`` template tag raises exceptions. This fixes a regression in
+  Oscar 2 where thumbnailing errors resulted in exceptions being propagated,
+  contrary to Django's recommendations that template tags should never
+  raise exceptions.