Pacify the grumpy VS Code tsconfig analyzer.

Author: chriskrycho

blueprints/ember-cli-typescript/files/tsconfig.json

@@ -7,7 +7,7 @@
     "noEmit": true,
     "sourceMap": true,
     "baseUrl": ".",
-    "modules": "ES6",
+    "module": "es6",
     "paths": {
       "<%= dasherizedPackageName %>/tests/*": ["tests/*"],
       "<%= dasherizedPackageName %>/*": [