Update package.json

Author: ffMathy

package.json

@@ -2,7 +2,7 @@
   "name": "@fluffy-spoon/substitute",
   "version": "1.0.0",
   "description": "",
-  "main": "Index.ts",
+  "main": ".src/index.ts",
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1"
   },