Add the drafts to the changelog.

Author: Julian

CHANGELOG.rst

@@ -1,6 +1,8 @@
 v4.0.0 (Not Yet Released)
 -------------------------
 
+* Support for Draft 2020-12 (as well as 2019-09). Big thanks to Thomas Schmidt
+  and Harald Nezbeda.
 * ``False`` and ``0`` are now properly considered non-equal even
   recursively within a container (#686). As part of this change,
   ``uniqueItems`` validation may be *slower* in some cases. Please feel