CI: github: reintroduce openssl 1.1.1

OpenSSL 1.1.1 is not tested anymore since github updated "ubuntu-latest"
to 22.04, let's reintroduce this version.
diff --git a/.github/matrix.py b/.github/matrix.py
index cde2bbe..98d0a1f 100755
--- a/.github/matrix.py
+++ b/.github/matrix.py
@@ -128,6 +128,7 @@
     for ssl in [
         "stock",
         "OPENSSL_VERSION=1.0.2u",
+        "OPENSSL_VERSION=1.1.1s",
         "OPENSSL_VERSION=latest",
         "LIBRESSL_VERSION=latest",
         "QUICTLS=yes",