Bump node-fetch from 1.7.3 to 2.6.1

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](https://github.com/bitinn/node-fetch/compare/1.7.3...v2.6.1)

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

package.json

@@ -49,7 +49,7 @@
     "jwk-to-pem": "^1.2.6",
     "moment-timezone": "^0.5.13",
     "mysql": "^2.13.0",
-    "node-fetch": "^1.6.3",
+    "node-fetch": "^2.6.1",
     "oidc-client": "^1.3.0-beta.3",
     "react": "^15.4.2",
     "react-big-calendar": "^0.13.0",