Bump node-fetch from 1.7.3 to 2.6.1 in /samples/react-adal-bot/bot

Bumps [node-fetch](https://github.com/bitinn/node-fetch) from 1.7.3 to 2.6.1.
- [Release notes](https://github.com/bitinn/node-fetch/releases)
- [Changelog](https://github.com/node-fetch/node-fetch/blob/master/docs/CHANGELOG.md)
- [Commits](node-fetch/node-fetch@1.7.3...v2.6.1)

Signed-off-by: dependabot[bot] <support@github.com>

samples/react-adal-bot/bot/package.json

@@ -21,7 +21,7 @@
   "dependencies": {
     "adal-node": "0.1.28",
     "botbuilder": "3.15.0",
-    "node-fetch": "^1.6.3",
+    "node-fetch": "^2.6.1",
     "restify": "7.2.1",
     "es6-promise": "4.2.4"
   }