Added it as an optional peerDependency

Author: hsubox76

packages/auth/package.json

@@ -103,7 +103,13 @@
     "typings:public": "node ../../scripts/build/use_typings.js ./dist/auth-public.d.ts"
   },
   "peerDependencies": {
-    "@firebase/app": "0.x"
+    "@firebase/app": "0.x",
+    "@react-native-async-storage/async-storage": "^1.18.1"
+  },
+  "peerDependenciesMeta": {
+    "@react-native-async-storage/async-storage": {
+      "optional": true
+    }
   },
   "dependencies": {
     "@firebase/component": "0.6.4",