[2.7] bpo-33127: Compatibility patch for LibreSSL 2.7.0 (GH-6210) (GH-6215)

LibreSSL 2.7 introduced OpenSSL 1.1.0 API. The ssl module now detects
LibreSSL 2.7 and only provides API shims for OpenSSL < 1.1.0 and
LibreSSL < 2.7.

Documentation updates and fixes for failing tests will be provided in
another patch set.

Signed-off-by: Christian Heimes <christian@python.org>.
(cherry picked from commit 4ca0739c9d97ac7cd45499e0d31be68dc659d0e1)

Co-authored-by: Christian Heimes <christian@python.org>
diff --git a/Tools/ssl/multissltests.py b/Tools/ssl/multissltests.py
index 994e420..ffc57f0 100755
--- a/Tools/ssl/multissltests.py
+++ b/Tools/ssl/multissltests.py
@@ -58,8 +58,9 @@
 ]
 
 LIBRESSL_RECENT_VERSIONS = [
-    "2.5.3",
     "2.5.5",
+    "2.6.4",
+    "2.7.1",
 ]
 
 # store files in ../multissl