wsgi_test: Cap TLS version at 1.2

On py310, tests may attempt to use TLS 1.3 which apparently doesn't like
the abrupt disconnect. Instead, it would complain:

    ssl.SSLEOFError: EOF occurred in violation of protocol

tests/wsgi_test.py

@@ -579,7 +579,8 @@ def wsgi_app(environ, start_response):
         sock = eventlet.wrap_ssl(
             eventlet.listen(('localhost', 0)),
             certfile=certificate_file, keyfile=private_key_file,
-            server_side=True)
+            server_side=True,
+            ssl_version=ssl.PROTOCOL_TLSv1_2)
         server_coro = eventlet.spawn(server, sock, wsgi_app, self.logfile)
 
         client = eventlet.connect(('localhost', sock.getsockname()[1]))