Bump version to 0.4.0 in package.json

Author: ProgrammerKR

extension/package.json

@@ -2,7 +2,7 @@
   "name": "proxpl",
   "displayName": "ProXPL Language Support",
   "description": "Syntax highlighting and language support for the ProXPL programming language",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "publisher": "ProXentix",
   "repository": {
     "type": "git",
@@ -111,4 +111,4 @@
     "url": "https://github.com/ProgrammerKR/ProXPL/issues"
   },
   "homepage": "https://github.com/ProgrammerKR/ProXPL#readme"
-}
+}