Update extension version for 1.15.0-beta6 and fix deprecated category

Author: DustinCampbell

package.json

@@ -1,7 +1,7 @@
 {
   "name": "csharp",
   "publisher": "ms-vscode",
-  "version": "1.15.0-beta5",
+  "version": "1.15.0-beta6",
   "description": "C# for Visual Studio Code (powered by OmniSharp).",
   "displayName": "C#",
   "author": "Microsoft Corporation",
@@ -17,7 +17,7 @@
   },
   "categories": [
     "Debuggers",
-    "Languages",
+    "Programming Languages",
     "Linters",
     "Snippets"
   ],