- Add downport-Sphinx-features.patch to make documentation
buildable even on SLE-15.

- Update to 3.9.17:
- gh-103142: The version of OpenSSL used in Windows and
Mac installers has been upgraded to 1.1.1u to address
CVE-2023-2650, CVE-2023-0465, CVE-2023-0466, CVE-2023-0464,
as well as CVE-2023-0286, CVE-2022-4303, and CVE-2022-4303
fixed previously in 1.1.1t (gh-101727).
- gh-102153: urllib.parse.urlsplit() now strips leading C0
control and space characters following the specification for
URLs defined by WHATWG in response to CVE-2023-24329
(bsc#1208471).
- gh-99889: Fixed a security in flaw in uu.decode() that could
allow for directory traversal based on the input if no
out_file was specified.
- gh-104049: Do not expose the local on-disk
location in directory indexes produced by
http.client.SimpleHTTPRequestHandler.
- gh-103935: trace.__main__ now uses io.open_code() for files
to be executed instead of raw open().
- gh-102953: The extraction methods in tarfile, and
shutil.unpack_archive(), have a new filter argument that
allows limiting tar features than may be surprising or
dangerous, such as creating files outside the destination
directory. See Extraction filters for details (fixing
CVE-2007-4559, bsc#1203750).
- gh-102126: Fixed a deadlock at shutdown when clearing thread
states if any finalizer tries to acquire the runtime head
lock.