fix: packages/demo/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-NODEFETCH-2342118
- https://snyk.io/vuln/SNYK-JS-NODEFETCH-674311

packages/demo/package.json

@@ -11,12 +11,12 @@
     "postinstall": "expo-yarn-workspaces postinstall"
   },
   "dependencies": {
-    "expo": "^33.0.0",
+    "expo": "^45.0.0",
     "react": "16.8.3",
     "react-dom": "^16.8.6",
     "react-native": "https://github.com/expo/react-native/archive/sdk-33.0.0.tar.gz",
     "react-native-debug-console": "^2.0.0-alpha.17",
-    "react-native-web": "0.11.4"
+    "react-native-web": "0.15.0"
   },
   "devDependencies": {
     "@babel/runtime": "^7.5.0",

yarn.lock

@@ -15221,9 +15221,9 @@ xtend@^4.0.0, xtend@~4.0.1:
   integrity sha1-pcbVMr5lbiPbgg77lDofBJmNY68=
 
 y18n@^3.2.1:
-  version "3.2.1"
-  resolved "https://registry.yarnpkg.com/y18n/-/y18n-3.2.1.tgz#6d15fba884c08679c0d77e88e7759e811e07fa41"
-  integrity sha1-bRX7qITAhnnA136I53WegR4H+kE=
+  version "3.2.2"
+  resolved "https://registry.yarnpkg.com/y18n/-/y18n-3.2.2.tgz#85c901bd6470ce71fc4bb723ad209b70f7f28696"
+  integrity sha512-uGZHXkHnhF0XeeAPgnKfPv1bgKAYyVvmNL1xlKsPYZPaIHxGti2hHqvOCQv71XMsLxu1QjergkqogUnms5D3YQ==
 
 "y18n@^3.2.1 || ^4.0.0", y18n@^4.0.0:
   version "4.0.0"