fix: signal to webpack that there's no side effects (#632)

Author: stipsan

package.json

@@ -31,6 +31,8 @@
     "test": "jest -c integration/jest.config.js",
     "typecheck": "tsc --noEmit"
   },
+  "sideEffects": false,
+  "typings": "typings/index.d.ts",
   "devDependencies": {
     "@babel/cli": "7.8.3",
     "@babel/core": "7.8.3",
@@ -118,6 +120,5 @@
     "prepare": [
       "@semantic-release/npm"
     ]
-  },
-  "typings": "typings/index.d.ts"
+  }
 }