Update version.

Author: sean-mcmanus

Extension/package.json

@@ -2,7 +2,7 @@
   "name": "cpptools",
   "displayName": "C/C++",
   "description": "C/C++ IntelliSense, debugging, and code browsing.",
-  "version": "0.23.1-master",
+  "version": "0.23.1",
   "publisher": "ms-vscode",
   "preview": true,
   "icon": "LanguageCCPP_color_128x.png",