Mark package as side effect free (#628)

Webpack introduced a convention of being able mark a package as side effect free so it can be tree shaken. This is safe as long as importing the module doesn't have side effects.

Co-authored-by: David Patrick <[email protected]>

package.json

@@ -3,6 +3,7 @@
   "version": "2.35.1",
   "description": "SDK for Auth0 API v2",
   "main": "src/index.js",
+  "sideEffects": false,
   "files": [
     "src"
   ],