Add changelog entry

2021-03-31 10:14:16 -05:00 · 2021-03-31 10:14:16 -05:00 · 4230afedbb
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+## 4.0.0 - 2021-03-31
+
+* Drop support for Python 2 in RST rendering [#1456](https://github.com/github/markup/pull/1456)
+
 ## 3.0.5 - 2020-11-12

 * Add commonmarker_exts to commonmarker options [#1268](https://github.com/github/markup/pull/1268)