fix: add files field to ensure index.js is included in git installs

Author: sippsolutions

package.json

@@ -8,6 +8,11 @@
     "aem": "./index.js",
     "hlx": "./index.js"
   },
+  "files": [
+    "index.js",
+    "src/",
+    "packages/"
+  ],
   "scripts": {
     "check": "npm run lint && npm run test",
     "test": "c8 mocha",