Bump node-fetch from 2.3.0 to 2.6.1

Bumps [node-fetch](https://github.com/bitinn/node-fetch) from 2.3.0 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@v2.3.0...v2.6.1)

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

package.json

@@ -21,7 +21,7 @@
     "boom": "^7.3.0",
     "express": "^4.16.4",
     "jest": "^24.1.0",
-    "node-fetch": "^2.3.0",
+    "node-fetch": "^2.6.1",
     "pg": "^7.8.0",
     "promise-retry": "^1.1.1",
     "supertest": "^3.4.2"