Upgrade prop-types to ^15.6.2

mobile/package-lock.json

@@ -11913,11 +11913,10 @@
       "dev": true
     },
     "prop-types": {
-      "version": "15.6.1",
-      "resolved": "https://registry.npmjs.org/prop-types/-/prop-types-15.6.1.tgz",
-      "integrity": "sha512-4ec7bY1Y66LymSUOH/zARVYObB23AT2h8cf6e/O6ZALB/N0sqZFEx7rq6EYPX2MkOdKORuooI/H5k9TlR4q7kQ==",
+      "version": "15.6.2",
+      "resolved": "https://registry.npmjs.org/prop-types/-/prop-types-15.6.2.tgz",
+      "integrity": "sha512-3pboPvLiWD7dkI3qf3KbUe6hKFKa52w+AE0VCqECtf+QHAKgOL37tTaNCnuX1nAAQ4ZhyP+kYVKf8rLmJ/feDQ==",
       "requires": {
-        "fbjs": "^0.8.16",
         "loose-envify": "^1.3.1",
         "object-assign": "^4.1.1"
       }

mobile/package.json

@@ -8,7 +8,7 @@
     "@storybook/react-native": "^3.4.11",
     "expo-cli": "^2.7.1",
     "expokit": "^32.0.6",
-    "prop-types": "15.6.1",
+    "prop-types": "^15.6.2",
     "protobufjs": "^6.8.8",
     "sinon": "^6.1.5"
   },