Update master version to 1.5.0-beta1

package.json

@@ -1,7 +1,7 @@
 {
   "name": "csharp",
   "publisher": "ms-vscode",
-  "version": "1.4.0-beta9",
+  "version": "1.5.0-beta1",
   "description": "C# for Visual Studio Code (powered by OmniSharp).",
   "displayName": "C#",
   "author": "Microsoft Corporation",