Add PR number to changelog.
MODIFY
CHANGES.rst
CHANGES.rst
@@ -15,7 +15,7 @@ dev (master)
* Fixed compatibility for cookiejar. (Issue #1229)
-* pyopenssl: Use vendored version of ``six``.
+* pyopenssl: Use vendored version of ``six``. (Issue #1231)
* ... [Short description of non-trivial change.] (Issue #)

Add PR number to changelog.