chore: add format script to package.json

Author: mgcrea

package.json

@@ -23,6 +23,7 @@
     "open:ios": "cd example; npm run open:ios",
     "codegen:ios": "rm -rf ios/generated; node node_modules/react-native/scripts/generate-codegen-artifacts.js -p . -t ios -s library",
     "lint": "eslint .",
+    "format": "prettier --write src/",
     "check": "tsc --noEmit",
     "spec": "NODE_OPTIONS=--experimental-require-module jest",
     "test": "npm run lint && npm run check && npm run spec",