Prepare 2.3.1

PCManticore · PCManticore · commit 09d561c0aa25 · 2019-10-09T09:29:13.000+02:00
diff --git a/ChangeLog b/ChangeLog
@@ -4,7 +4,7 @@ astroid's ChangeLog
 
 What's New in astroid 2.3.1?
 ============================
-Release Date: TBA
+Release Date: 2019-09-30
 
 * A transform for the builtin `dataclasses` module was added.
 
