bpo-31346: Use PROTOCOL_TLS_CLIENT/SERVER (#3058)

Replaces PROTOCOL_TLSv* and PROTOCOL_SSLv23 with PROTOCOL_TLS_CLIENT and
PROTOCOL_TLS_SERVER.

Signed-off-by: Christian Heimes <christian@python.org>
diff --git a/Lib/asyncio/test_utils.py b/Lib/asyncio/test_utils.py
index ecb3fca..6580594 100644
--- a/Lib/asyncio/test_utils.py
+++ b/Lib/asyncio/test_utils.py
@@ -45,7 +45,7 @@
     if ssl is None:
         return None
     else:
-        return ssl.SSLContext(ssl.PROTOCOL_SSLv23)
+        return ssl.SSLContext(ssl.PROTOCOL_TLS)
 
 
 def run_briefly(loop):