bpo-38820: Test with OpenSSL 3.0.0-alpha15 (GH-25537)

Signed-off-by: Christian Heimes <christian@python.org>
diff --git a/Tools/ssl/multissltests.py b/Tools/ssl/multissltests.py
index 90213b3..dc47c5c 100755
--- a/Tools/ssl/multissltests.py
+++ b/Tools/ssl/multissltests.py
@@ -47,7 +47,7 @@
 
 OPENSSL_RECENT_VERSIONS = [
     "1.1.1k",
-    "3.0.0-alpha14"
+    "3.0.0-alpha15"
 ]
 
 LIBRESSL_OLD_VERSIONS = [