Bump required VS Code version to 1.18

Bump required VS Code version to 1.18 due to new command

Author: auchenberg

package.json

@@ -2,10 +2,10 @@
     "name": "sublime-keybindings",
     "displayName": "Sublime Text Keymap",
     "description": "Popular Sublime Text keybindings for VS Code.",
-    "version": "3.0.2",
+    "version": "3.0.3",
     "publisher": "ms-vscode",
     "engines": {
-        "vscode": "^1.6.0"
+        "vscode": "^1.18.0"
     },
     "categories": [
         "Keymaps"