[3.8] Add whatsnew for removal of asyncio.loop.create_datagram_endpoint()'s *reuse_address* parameter (GH-17595). (#17630)

(cherry picked from commit f501db2b93)

Co-authored-by: Kyle Stanley <aeros167@gmail.com>

Doc/whatsnew/3.6.rst

@@ -2433,3 +2433,13 @@ In 3.6.7 the :mod:`tokenize` module now implicitly emits a ``NEWLINE`` token
 when provided with input that does not have a trailing new line.  This behavior
 now matches what the C tokenizer does internally.
 (Contributed by Ammar Askar in :issue:`33899`.)
+
+Notable changes in Python 3.6.10
+================================
+
+Due to significant security concerns, the *reuse_address* parameter of
+:meth:`asyncio.loop.create_datagram_endpoint` is no longer supported. This is
+because of the behavior of the socket option ``SO_REUSEADDR`` in UDP. For more
+details, see the documentation for ``loop.create_datagram_endpoint()``.
+(Contributed by Kyle Stanley, Antoine Pitrou, and Yury Selivanov in
+:issue:`37228`.)

Doc/whatsnew/3.7.rst

@@ -2541,3 +2541,13 @@ This resolves a long standing issue where all virtual environments would have
 to be upgraded or recreated with each Python update. However, note that this
 release will still require recreation of virtual environments in order to get
 the new scripts.
+
+Notable changes in Python 3.7.6
+===============================
+
+Due to significant security concerns, the *reuse_address* parameter of
+:meth:`asyncio.loop.create_datagram_endpoint` is no longer supported. This is
+because of the behavior of the socket option ``SO_REUSEADDR`` in UDP. For more
+details, see the documentation for ``loop.create_datagram_endpoint()``.
+(Contributed by Kyle Stanley, Antoine Pitrou, and Yury Selivanov in
+:issue:`37228`.)

Doc/whatsnew/3.8.rst

@@ -2206,3 +2206,13 @@ Here's a summary of performance improvements since Python 3.3:
         loop_overhead                    0.3     0.5     0.6     0.4     0.3     0.3
 
     (Measured from the macOS 64-bit builds found at python.org)
+
+Notable changes in Python 3.8.1
+===============================
+
+Due to significant security concerns, the *reuse_address* parameter of
+:meth:`asyncio.loop.create_datagram_endpoint` is no longer supported. This is
+because of the behavior of the socket option ``SO_REUSEADDR`` in UDP. For more
+details, see the documentation for ``loop.create_datagram_endpoint()``.
+(Contributed by Kyle Stanley, Antoine Pitrou, and Yury Selivanov in
+:issue:`37228`.)