CI: github: switch to OpenSSL 3.0.0

Switch the OpenSSL 3.0.0alpha17 version to the final 3.0.0 release.

Part of OpenSSL 3.0.0 portage. (ticket #1276)
diff --git a/.github/matrix.py b/.github/matrix.py
index e3334a0..5686760 100755
--- a/.github/matrix.py
+++ b/.github/matrix.py
@@ -110,7 +110,7 @@
     for ssl in [
         "stock",
         "OPENSSL_VERSION=1.0.2u",
-        "OPENSSL_VERSION=3.0.0-alpha17",
+        "OPENSSL_VERSION=3.0.0",
         "LIBRESSL_VERSION=2.9.2",
         "LIBRESSL_VERSION=3.3.3",
 #        "BORINGSSL=yes",