Updated package to use flow as dev dependency

babel.config.js

 module.exports = function(api) {
   api.cache(true);
   return {
-    presets: ['babel-preset-expo'],
+    presets: ['babel-preset-expo', '@babel/preset-flow'],
     env: {
       production: {
         plugins: ['react-native-paper/babel'],

package.json

     "react-native-webview": "7.4.3"
   },
   "devDependencies": {
+    "@babel/cli": "^7.8.4",
+    "@babel/core": "^7.9.0",
+    "@babel/preset-flow": "^7.9.0",
     "babel-preset-expo": "^8.0.0",
+    "flow-bin": "^0.122.0",
     "jest": "^25.1.0",
     "jest-extended": "^0.11.5",
     "react-test-renderer": "^16.13.1"