Add sideEffects: false to package json (#54)

This allows removing this library when DCE is performed.

Author: JoviDeCroock

package.json

@@ -15,6 +15,7 @@
     "dist",
     "index.d.ts"
   ],
+  "sideEffects": false,
   "types": "index.d.ts",
   "scripts": {
     "prepublishOnly": "run-s build",